[win32] Move windows-specific defines from source into CMakeLists.txt

- Just define WIN32_LEAN_AND_MEAN, VC_EXTRALEAN and NOMINMAX globally to avoid
  headaches related to stray macros and stuff.
[win32] Make UMVE CMakeLists.txt work
Merge branch 'win32' of https://github.com/Waldteufel/mve into win32

Conflicts:
	CMakeLists.txt
Merge branch 'win32' of https://github.com/andre-schulz/mve into win32