Removed trailing _d from OSX libraries, OSX uses a directory based naming convention to handle libraries configuration differences
Removed Debug suffix completely based on input from Tom Mason @wheybags and general usage within other projects.  Continuous integration builds use separate directories for build configuration type which works as well as the name suffix
Merge pull request #173 from libRocket/feature/cmake-osx-lib-naming-convention

Removed CMAKE_DEBUG_POSTFIX as it is easily accomplished by building with different output directories and referencing the libraries this way from within dependent projects