[duneproject,release] Let new modules create CMake package configuration files with autotools.
[am2cmake,release] Add directives for CMake package configuration with autotools during conversion
[release,parallel] Suppress unused parameter warnings without DUNE_ISTL_WITH_CHECKING
[buildsystem,bugfix] Test for the right directories when creating package configuration files.

Due to testing the wrong directories some variables where missing in the
package configuration files. This patch fixes this.
[cmake,bugfix] Handle case where module search path is not in list.

With new modules there were cases where cmake/modules was not in the
modules path which made configuration fail. This patch fixes this case.
[bugfix,duneproject] Makes duneproject work again with installed modules.

duneproject failed miserably when run with only installed modules. With
this patch we correctly setup the pkg-config and dunecontrol path to
handle this situation. In addition we fixed various issues with the newly
created modules and they now build as exspected.