[grid.provider.interface] expose base methods in ProviderInterface
[grid.boundaryinfo] added BoundaryInfoConfigs

I was tired of always figuring out the correct intersection so I decided to
put the default_config() of the BoundaryInfos into separate
BoundaryInfoConfigs, each with the same name as the original BoundaryInfo.
Those are not templatized and can be easily carried around and converted
to a BoundaryInfo using the BoundaryInfoProvider once the IntersectionType
is known.
[la.container.common] added ctor taking a DenseMatrix< T >
[la.container.eigen] added several ctors to EigenDenseMatrix
* one taking a MatrixInterface< M > and
* one taking a DenseMatrix< T >
[common.convergence-study] whitespace
[functions.ESV2007] extended signature of Cutoff

And implemented the current variant as a specialization. This allows us to
add a 2nd variant taking a diffusion factor and a diffusion tensor.
[functions.ESV2007] added first draft of a 2nd variant to playground

This one takes a diffusion factor and a diffusion tensor.
[common.fmatrix] added another operator*

This time we allow to multiply a RxC and a 1xC matrix by taking the
transposed of the right matrix. This is mathematically incorrect, of
course, but since a FieldMatrix has no means to be transposed this is it
then.
[pg] norm shorthand for gdt df
[df] msfem. proj. for gdt adjustments
[df] fixes msfem proj for real
[common.fvector] added a FieldVector variant with sane ctors
[functions.interfaces] define types once and inherit them everywhere
[grid] fixes gcc 4.8 compile error with missing FakeEntity field
[common.fmatrix]
* provide empty ctor
* disable checks in NDEBUG environment
* specify Dune::FieldVector (in contrast to Stuff::Common::FieldVector)
[stuff.common.fvector] provide default ctor
[common.configtree] added support for stuff variants of fvector/fmatrix
[functions.spe10] added 2 -> 2x2 variant

This is just the unit matrix scaled by the Kx value, not the actual 2d
Spe10 data.
[grid.fakeentity] whitespce

The whitespace here was on purpose for reasons documented inside my head.
[functions] ability to auto-transfer a globalfunction to diff. entitytype