Note remove_reference is necessary, because you cannot extract the iterator type from
row_reference directly in case: row_reference == row_type&

IteratorFacades::Pointer is assumed to be T* which is not the case for row_reference != row_type&.

Add additional template parameter R (default T&) to handle the case row_reference != row_type&.

This patch introduces a new macro DUNE_UNUSED_PARAMETER(parm) for marking
unused parameters that are there for a purpose (e.g. the prescribed interfac
The macro simply performs a cast to void. In addition all unused parameter w
that I found were removed.

This fixes a Clang warning.

Make more precise statement to the user if no template specialization
of DenseMatrixAssigner is found. Also use dune_static_assert instead of
static_assert.

The default implementation of DenseMatrixAssigner replaces redundant
code in dense matrix constructors taking a primitive data type.

[DenseMatrix] Introduce DenseMatrixAssigner for initializing dense matrices from arbitrary right hand sides

In order to overcome the deficiencies of istl_assign_to_fmatrix() we
propose to always use a struct DenseMatrixAssigner for initializing a
dense matrix. This class can be specialized by users for any right hand
side to be used in an assignment.  The new mechanism can bei default
implemented using existing implementations of istl_assign_to_fmatrix()
as well.

This fixes FS#1317 for me (use invert for 2x2 matrix with
std::complex< long double >).
The problem is that 1.0 is a double, which can be converted implicitly
to a long double which, in turn, could be converted implicitly into a
std::complex< long double >. However, the compiler does not use two
implicit type conversions, so double cannot be divided by a
std::complex< long double >.

Patch by Elias Pipping

[[Imported from SVN: r6915]]

As suggested by Christian in FS 1147.

Implemented by Elias Pipping.

[[Imported from SVN: r6913]]

This fixes FS 1147.  Thanks to Elias Pipping for the patch.

[[Imported from SVN: r6819]]

With the exception of mpicollectivecommunication.hh
and propertymap.hh, which I didn't understand.

[[Imported from SVN: r6784]]

[[Imported from SVN: r6714]]

Backported from Martin's development branch,
minus some whitespace changes.  Thanks.

[[Imported from SVN: r6712]]

[[Imported from SVN: r6708]]

[[Imported from SVN: r6677]]

[[Imported from SVN: r6558]]

[[Imported from SVN: r6534]]

[[Imported from SVN: r6533]]

See FS#966.

[[Imported from SVN: r6521]]

[[Imported from SVN: r6512]]

[[Imported from SVN: r6495]]

[[Imported from SVN: r6370]]

[[Imported from SVN: r6369]]

rbegin -> beforeEnd
rend   -> beforeBegin

[[Imported from SVN: r6286]]

[[Imported from SVN: r6268]]

use className to get a better error message when a specialization of istl_assign_to_fmatrix is missing

[[Imported from SVN: r6250]]

[[Imported from SVN: r6247]]

[[Imported from SVN: r6234]]

[[Imported from SVN: r6210]]

[[Imported from SVN: r6206]]

[[Imported from SVN: r6205]]

[[Imported from SVN: r6185]]

* factor out most of the FieldMatrix math methods

missing: several functions oculd not me moved, as they require som
		 kind of type promotion traits

[[Imported from SVN: r6181]]