-- Added support in the msvc toolchain for Visual Studio 2015.
-- Changed how the include and lib paths in the msvc toolchain are formed so the logic is much simpler, more accurate, and compatible with all versions that have and will have properties set through vcvarsall.bat.
-- Removed the bin path from the msvc toolchain. Because we overwrite the 'Path' env variable, having a full path to the tool binaries is unnecessary. The 'Path' var will ensure the correct tools are used.