Improvements on wares declaration macros for better maintenance

* Added internal macros for declaration 
  of standard functions for plugins

(closes OpenFLUID/openfluid#421)
Improvements on display of paths in OpenFLUID-Builder

(closes OpenFLUID/openfluid#420)
Cleaning of code and switch to version 2.0.1~rc1

* Updated changelog
* Cleared some warnings at build

(references OpenFLUID/openfluid#33)