2017-05 upstream merge

See merge request !1

* upstream/master: (298 commits)
  Prepend `-std=c++xy` flag before user-supplied flags
  [TypeList] Don't needlessly instanciate type traits objects.
  [TypeList] Make a unit test.
  use Doxygen comments instead of noexcept(false)
  [cleanup] mark all methods of Timer as noexcept
  [cleanup] fix pedantic warnings about extra ;
  [cleanup] include header for std::function
  [cleanup] replace throw with noexcept
  Use `Dune::TestSuite` instead of `assert`
  Silence expected deprecation warning in test
  [feature][OverloadCompilerFlags] Also allow for CFLAGS to be overloaded.
  [feature][OverloadCompilerFlags] cache string with default compiler flags passed on initial cmake call. Also, compiler.sh should be cxx_compiler.sh since we are only wrapping the CXX compiler.
  [AlignedNumber] Cleanup.
  Use `override` instead of `virtual`
  [cleanup] remove extra semicolons
  unify namespaces
  [doc] document fully static binaries, but turn them off by  default
  [doc,mingw] move example configurations to thee docs
  [doc] mention how to set cmake variables from an opts file
  [doc] adjust the sphinx layout to match better to the dune design
  ...

Prepend `-std=c++xy` flag before user-supplied flags

See merge request !243

Appending the automatically detected `-std=c++xy` flag means any
user-provided flag will get silently overridden.  Prepending it
instead makes it easier for users to override the default option as
they no longer have to set `DISABLE_CXX_VERSION_CHECK`.

Arithmetic types for alignment debugging

See merge request !226

Configure time virtualenv setup

See merge request !220

dune-python migration

See merge request !219

Unit test for TypeList

See merge request !239

That can lead to problems when template parameters of the traits classes are
noninstantiable.

[cleanup] fix some GCC 7 warnings

Closes #71

See merge request !236

All methods only use expressions that are noexcept, so we should mark
the methods accordingly.

I also removed the TimerError exception that was never used.

Thanks to Simon Praetorius for pointing this out.

std::function is defined in <functional>. Prior to GCC 7 this header was
transitively included through other headers in the C++ Standard Library
but in GCC 7 these transitive includes have been removed.

See https://gcc.gnu.org/gcc-7/porting_to.html#header-dep-changes

throw(...) has been deprecated in C++17 and can be replaced with
noexcept(false).

Closes #71

Use `Dune::TestSuite` instead of `assert`

See merge request !235

Silence expected deprecation warning in test

See merge request !234

OverloadCompilerFlags: cache string with default compiler flags passed

See merge request !209

on initial cmake call. Also, compiler.sh should be cxx_compiler.sh since we are
only wrapping the CXX compiler.

Conflicts:
	dune/common/CMakeLists.txt

Do not mix the complete list of `<cmath>` functions with the incomplete list
of `<complex>` functions, but keep them seperate for easier maintenance.

Do include `<complex>` since we are using a function from that file.

Use `override` instead of `virtual`

See merge request !230

The `override` specifier makes sure that the function is virtual and
overrides a virtual function from the base class.

[cleanup] remove extra semicolons

See merge request !229

This gets rid of some warnings when compiling with -Wpedantic.

Implement specialized version of invert for 3x3 dense matrices.

See merge request !216

unify namespaces

See merge request !191

we decided that the internal namespaces shall be called "Impl".

Feature/mingw suppport

See merge request !224

Feature/match sphinx layout to dune

See merge request !228