* Add the CMake build system
* Use CMake as the default for new projects
* Change [fxsdk new] but continue supporting the previous signature
* Automatically configure in [fxsdk build-fx] and [fxsdk build-cg]
* Improve help screen
The fxSDK will no longer specify the final values for these parameters,
leaving them to the user in CMakeLists.txt or project.cfg, as reasonable
defaults are good enough.
This is because several libraries have separate binaries, and so are
linked with different command-line arguments, just like gint is linked
with -lgint-fx on one side and -lgint-cg on the other.
This makes it possible to change PREFIX at the last minute when running
install, effectively installing the files into a false packaging root
while retaining the same contents as if installed normally.