[Cpptool-develop] Preprocessor implementation added to repository

[Andre B. <and...@gm...>]

I have just added the current implementation. Some small tests are 
written in preprocessor unit test code.
However <include> mechanism has been deactivated in the plugins because 
no implementation for open
and changing multiple files is done yet (look at interface 
'sourcemanager'). AstDumper uses a simple
implementation of sourcemanager accessing the header files by file 
system (FileSourceManager) - however
 the limitations of parsing expressions of '#ifdef' and '#if' do not 
allow to parse usual system headers correctly.
For that reason I deactivcated the includes by setting the preprocessor 
option 'skipIncludes'.

Output of correct parsing error positions inside included files is wrong 
because of problems in position
translation. That problem needs to be checked.

not much time in the next weeks,
until later,
André