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
Merge pull request #118 from fabian1995/master

Alpha 1.2 Build 4
[fix][compiler] check if function or type is already declared in unierse scope
add array support inside checkForwardParams function
[fix][compiler] doesn't allow "a++" or "a--" if "a" is a const variable
[enh][tests] add new tests
Merge pull request #119 from pointhi/master

[fix][compiler] fix various compiler bugs
Merge pull request #120 from Peda1996/master

Small fixes