CMakeLists.txt:
- Changed branch of subprojects to "mac_os_x_rpath".
- Added <project>_SRC_DIR and <project>_BIN_DIR variables to be able to change them in one place if necessary.
- GLEW is now built out-of-source with Make’s VPATH. Also supports different build types by specifying DIST_NAME

cmake/toyrenderer_inject_variables.cmake.in:
- Insert the path to the compiled glew lib in the binary dir and to the include files in the source dir via the CMAKE_PREFIX_ PATH variable.
Merge branch 'mac_os_x_rpath'
CMakeLists.txt:
- Changed branch of subprojects to "master".