[Qt-creator] New preprocessor

[Erik Verbruggen]

Hello,

We have been taking a thorough look at the preprocessor in Qt Creator, 
and decided to finally fix all the small issues we had with it. So, in a 
couple of hours I will push a new version to master. Notable fixes:
- macros in macro bodies
- stringification of parameters [cpp.stringize]
- the concatenation operator [cpp.concat]
- #include MACRO_HERE
- defined() inside macro bodies used in pp-conditions.

Side-note: I also limited the amount of tokens that an expansion can 
generate to 5000 tokens. If you are wondering why, take a look at the 
"macro_pounder_fn.c" test-case.

For people with patches against the "old" preprocessor: I will try to 
incorporate them in subsequent patches, but I might have to ask you to 
change them to work against the new code. I am really sorry for the 
inconvenience.

Regards,
Erik.