add cmake paths for overriding defaults:

CMAKE_INSTALL_LIBDIR
CMAKE_INSTALL_BINDIR
CMAKE_INSTALL_CGIBINDIR
APACHE_MODULE_DIR

e.g.: use cmake -DCMAKE_INSTALL_LIBDIR=lib64 to install libraries to
/usr/local/lib64 instead of /usr/local/lib
Adjusting RPM spec file.
Merge branch 'master' of https://github.com/mapserver/mapcache
Merge branch 'master' into rpm

Conflicts:
	CMakeLists.txt