modul name (lower case with dashes).

These leads to kind of weired variabable names (dune-common_DIR,
dune-common_LIBRARIES, etc.) but finds non-installes modules
easier. You just sets CMAKE_PREFIX_PATH to the directory containing
the modules.

[[Imported from SVN: r6724]]

infrastructure to use the module with cmake.

Currently, only an installed dune-common can be used, as the others
lack the cmake confguration files. One has to provide the
CMAKE_MODULE_PATH pointing to the directory where
e.g. DuneMacros.cmake is installed (PREFIX/share/cmake/modules) and 
DuneCommon_DIR pointing to PREFIXlib/cmake.

The ${CMAKE_BINARY_DIR}/config.h.cmake of the project is created such
that it includes section from modules that it depends on as well as
the ${CMAKE_SOURCE_DIR}/config.h.cmake. This prevents user from
creating a full file by hand.

Renamed package configuration files according to the style of the 
other modules.

[[Imported from SVN: r6661]]

[[Imported from SVN: r6643]]