Several fixes

+ several fixes
+ windoweventlistener
Merge pull request #116 from Peda1996/master

Several fixes
[enh][error_messages] add forgotten message
[enh][preprocessor] add new preprocessor implementation
[enh][preprocessor] add main part for ifdef support
[enh][gui] using new Preprocessor for gui
Merge pull request #117 from pointhi/master

add new preprocessor
Version update
Reference click detection in treetable
Finished Alpha 1.2 (Build