Fix GmshWriter test and make GmshWriter more robust and simple

This fix issues #3 and #4. 

See merge request !51

[gmshtest]: dump files in the build directorinstead of in the source directory, check IDs vector if not empty before accessing it, move cout inside check function to avoid redundancy

[gmshwriter] don't use pointers to pass physical IDs; this reduce the number of methods needed and make the code more robust since it now checks if the vectors are empty before trying to use them

fixes 8ab0677f…

Add insertionIndex and wasInserted to OnedDGrid

See merge request !49

[bugfix] resolve cyclic inculsion

The headercheck does not pass in the master, this fix makes headercheck pass.

See merge request !47

Note: This one sneaked silently through a back door during the removal of
entity pointers, although it is completely unrelated to the announced change.

Remove `EntityPointer` (part 2)

This merge request removes more uses of `EntityPointer`:

 - Many `EntityPointer` typedefs were removed.
 - `DGFWriter` no longer uses `EntityPointer`.
 - The `EntityPointer` template-parameter for the `GridTraits` was removed.
 - The deprecated `entityPointer()` method was removed.

See also flyspray/FS#1104

See merge request !46

Deprecate Intersection::codimension and Intersection::dimension

At the 2015 dev meeting we decided to deprecated and eventually remove the
two exported numbers Intersection::codimension and Intersection::dimension.
The main reasons where the a) they are redundant and b) having Intersection::dimension
denote the grid(!) dimension confused too many people.
(see http://users.dune-project.org/projects/dune-developer-meeting-2015/wiki/Protocol
Section 7.5.1.5 for the minutes of that discussion).

This patch deprecates the two numbers.  I tested it with clang-3.6.2 (where it works)
and gcc 5.3.1 (where it doesn't, but at least it doesn't break anything).

I plan to leave this open until monday 29.3. to give everybody a last chance for objections, and then merge it myself.

See merge request !43

Documentation: state explicitly that GeometryGrid::EntitySeed is consistent also after a grid modification



See merge request !42

[documenation] state explicitly that an EntitySeed is consistent also after a grid modification for what concern GeometryGrid

[cleanup] fix some typos in documentation strings

This fixes typos in comments and error messages.

See merge request !44

At the 2015 dev meeting we decided to deprecated and eventually remove the
two exported numbers Intersection::codimension and Intersection::dimension.
The main reasons where the a) they are redundant and b) having Intersection::dimension
denote the grid(!) dimension confused too many people.
(see http://users.dune-project.org/projects/dune-developer-meeting-2015/wiki/Protocol
Section 7.5.1.5 for the minutes of that discussion).

This patch deprecates the two numbers.  I tested it with clang-3.6.2 (where it works)
and gcc 5.3.1 (where it doesn't, but at least it doesn't break anything).

BLUE does figure in the UG enum type of possible 3D refinement rules,
but there seems to be no code at all implementing such rules.
I am unsure what the reason is:  is the enum wrong?  Or is it just being
optimistic and 3D BLUE rules were expected to be added eventually?

For the time being I simply remove 3D BLUE from the documentation of
anisotropic UGGrid refinement.

The UG library has always used two macros _2 and _3 to select the grid dimension.
These macros were set by the build system and changed all sorts of things, including
data structure layout.  Unfortunately, the names _2 and _3 are also used by the
C++ standard library, in the std::placeholders namespace.  For some reason, this
does not lead to problems using libstdc++, but apparently it does when using
libc++.

To fix this, in the UG git master (what will become ug 3.13.0), these two macros
have been renamed to UG_DIM_2 and UG_DIM_3, respectively.  As a consequence,
the Dune UGGrid wrapper now fails to compile with the UG git master.  As an
intermediate solution, this patch modifies UGGrid to always use both old and
new macros.  That way, at least users of libstdc++ can use the UG git master
again.  All others have to wait for a more clever patch.

Remove unused variable and silence a compiler warning



See merge request !41

The addresses the following compiler warning:

  dune/grid/uggrid/uggridintersections.cc:513:13: warning:
  unused variable ‘nSides’ [-Wunused-variable]

If the DGF file could not be found in the DGFGridFactory for YaspGrid,
you got the exception 'file not found in BasicBlock::BasicBlock'. As the
BasicBlock only gets an istream, it cannot display the filename.
Therefore, we directly check whether the ifstream is valid before
passing it anywhere. If not, we through an exception containing the
file name.

[bugfix] add missing header

Header `iostream` is not included but `std::cout` is used.

See merge request !37

[cmake] bump minimum required version

This is basically redundant, as dune-common requires it, but minimum
versions should be consistent among the core modules.

See merge request !36

[ug] Fix static assert for dimworld = 3



See merge request !35

This is basically redundant, as dune-common requires it, but minimum
versions should be consistent among the core modules.