Don't decide whether to preprocess .spec files based on Kernel-Mode vs. User-Mode...

Don't decide whether to preprocess .spec files based on Kernel-Mode vs. User-Mode, but on the file extension.
.pspec files are preprocessed now, while .spec files aren't. A change like this was already done in the amd64 branch before KJK rewrote the .spec stuff in rbuild.

- Renamed currently preprocessed .spec files to .pspec and changed that in the .rbuild files appropriately
- Renamed "IsWineModule" to "IsSpecDefinitionFile",  the new name is more appropriate
- Removed some checks for uppercased file extensions, we neither use them in our tree nor it will totally work as we only support them in a few places

Commit dedicated to Timo ;-)

svn path=/trunk/; revision=37070