[CMake] Recent changes in CVS

[Ken Martin]

Due to some performance problems with many small files on Windows I have
reworked the makefile generator again :-) I still have a bit to do (some
dependency issues where it is being too aggressive right now) but here is
what has been done. The makefile generator now produces far fewer files,
does not complain about unused custom commands (and there is a long term
reason for this) and it now hides much of the CMake crud into a CMakeFiles
subdirectory. If you are using CVS cmake you will want to wipe your binary
tree prior to using this. Otherwise you will be left with all the old files
from the prior version of the generator. So the next version of CMake
(2.2.1) will probably also be "beta" since there have been a bit too many
changes from 2.2.0 to make it a "real" release.

Thanks
Ken