See #63

[bugfix][albertagrid] fix failing assertion on comparison of intersection iterators

See merge request !223

When comparing two default-constructed intersection iterators for AlbertaGrid,
this would result in an assertion to fail (in debug mode only). Otherwise, the
code worked perfectly fine.

add a method to return the gridView instance on the MCMGMapper

See merge request !222

bump version to 2.7-git [ci skip]

See merge request !221

metnion changes to MCMGMapper in CHANGELOG

See merge request core/dune-grid!219

Always enable DUNE_GRID_EXPERIMENTAL_GRID_EXTENSIONS

See merge request core/dune-grid!155

remove CheckExperimentalGridExtenions and set the deprecated variable DUNE_GRID_EXPERIMENTAL_GRID_EXTENSIONS always to true

bugfix for checkidset for empty grids. [bugfix][checkidset] check whether begin != end before dereferencing

See merge request core/dune-grid!218

iterator.

Modify the MCMGMapper to store multiple dofs per geometry type

See merge request !215

Improve idset documentation

See merge request !217

I wanted to state a few assumptions on the IdType that have been
implicit all these years, like copy-assignability of and default
constructibility.  I ended up rewriting most of the class
documentation of the IdSet class, which hadn't been touched in
a long time.  I hope my changes are for the better.

[Yasp] StructuredGridFactory specialization should return `unique_ptr`

See merge request !216

f96b091d changed the
StructuredGridFactory to return a `unique_ptr` instead of a
`shared_ptr`.  This patch implements the same change for the
Yasp's specialization of the `StructuredGridFactory`.

generic datahandle class based on the mapper and a dense vector:
- size(geometryType) to return the number of dofs for a given geometry type
- types(codim) return a range over all geometry types of the given
  codimension on which data is attached

This patch modifies MCMGMapper such that multiple indices may be allocated
per geometry type. To this end, the layout function does no longer return a
bool but the number of indices to allocate for a given geometry type.
Old layout functions continue to work, because `bool` implicitly casts into
`std::size_t` such that `true` is 1 and `false` is 0 so that exactly one
index is allocated, if the geometry type was included in the layout.

Semantic enhancements:
- The `index` method returns the first index allocated for a geometry type
- The `contains` method returns whether at least one index was allocated
  for a geometry type (and fills in the first index).
- a new method `indices` returns an IntegralRange containing all indices
  allocated for a given geometry type. It can be used in a range-based-for
  like this:
  ```
  for( auto i : mapper.indices( element ) )
    doSomething( i );
  ```

communicate boundary data on GridPtr::loadBalance

See merge request !213

[ci] Stop testing with Debian 8

See merge request !209

Make method MessageBufferIF::read non-const

See merge request !214

StructuredGridFactory: return `unique_ptr` instead of `shared_ptr`

See merge request !212

The method CommDataHandleIF::scatter receives a non-const
reference to the message buffer.  This reference is
non-const because reading from the buffer advances the
internal iterator, and hence changes the buffer state.
However, the MessageBufferIF claims that the read method
is const.  This patch removes the const to make the
interface consistent.

Deprecate UniversalMapper and its header file

See merge request !200

Use new GeometryTypes namespace whereever possible

See merge request !211

Allow operator in analytical coordfunction v2

See merge request !205

A series of patches to reduce the number of compiler warnings

See merge request !208