- since CMake 3.5 the path to the cmake.exe is no longer by default written to Windows' PATH variable. Therefore this has to be done in the script.
- Windows path can contain spaces (CMake's default installation folder does) so we must use quotes around the paths
- set the CMAKE_PREFIX_PATH variable
As discussed on the list. If no C++11 compiler is found configuration stops
with an error. There are now unneeded parts of boost, the will be removed in
a second commit.