tries to find an installed module via pkg-config. If pkg-config finds
an installed module, dunecontrol proceeds, although the module is
dropped from the internal tree, as installed modules don't need to be
built. If pkg-config does not find the module, an error is throughn.
If a dune.module file is found, installed versions of the module are
ignored.


[[Imported from SVN: r4741]]

[[Imported from SVN: r4740]]

link for GRAPE. 


[[Imported from SVN: r4739]]

[[Imported from SVN: r4738]]

[[Imported from SVN: r4737]]

[[Imported from SVN: r4736]]

[[Imported from SVN: r4735]]

[[Imported from SVN: r4734]]

[[Imported from SVN: r4733]]

[[Imported from SVN: r4732]]

[[Imported from SVN: r4731]]

This fix ensures, that for example -I'dune-common' is only added once to
the DUNE_CPPFLAGS. 


[[Imported from SVN: r4730]]

and solve() is chosen.  So far, this was done be specializing  auxiliary helper classes.
I replaced this with simple if (n==...).  One would think that a compiler should be able
to optimize this away.

Indeed: measurements using g++-4.1 showed that there is no speed difference when compiled
with -O3.  When compiled without optimization, the new code is actually about 25%
_faster_ than the old one!  Good for them users of block Gauss-Seidel!

[[Imported from SVN: r4729]]

[[Imported from SVN: r4728]]

[[Imported from SVN: r4727]]

[[Imported from SVN: r4726]]

[[Imported from SVN: r4725]]

[[Imported from SVN: r4724]]

[[Imported from SVN: r4723]]

[[Imported from SVN: r4722]]

* added support for environment variables $MAKE and $GREP to dunecontrol
* updated buildsystemhowto

[[Imported from SVN: r4721]]

[[Imported from SVN: r4720]]

[[Imported from SVN: r4719]]

[[Imported from SVN: r4718]]

[[Imported from SVN: r4717]]

[[Imported from SVN: r4716]]

[[Imported from SVN: r4715]]

[[Imported from SVN: r4714]]

[[Imported from SVN: r4713]]

[[Imported from SVN: r4712]]

[[Imported from SVN: r4711]]

be a .cc file which in this case is not a good idea. 
The singletons are now created in the instance method and the instance
pointer is not needed anymore. 



[[Imported from SVN: r4710]]

troubles when using mpicxx and there are only shared lib of mpi.



[[Imported from SVN: r4709]]

on many systems dvips tries to print directly

[[Imported from SVN: r4708]]

[[Imported from SVN: r4707]]

[[Imported from SVN: r4706]]

[[Imported from SVN: r4705]]

[[Imported from SVN: r4704]]

[[Imported from SVN: r4703]]

Many thanks to Klaus Schneider for the hint!

[[Imported from SVN: r4702]]