Rename all library targets to start with wx. This way it does not use generic
names like base or core that could interfere with other libraries that add
include the wxWidgets project.
Add 'BEFORE' to target_include_directories so we include the headers
of the buildin third-party libraries before headers of third-party
libraries included in wxTOOLKIT_INCLUDE_DIRS.
Add CMake build system for libraries, tests and samples
update_files.py converts build/files into CMake format.
build/update-setup-h has been modified to update build/cmake/setup.h.in.
