Updated README

* Added into README module source explanation
* Commented cmake search for gthread library
Added INSTALL file
Added function 'addCSVOutput'

* Added function 'addCSVOutput'
* Splitted internal initialisation of OpenFLUID vars
* Added PyOpenFLUID csv format
Added addCSVOutput doc

* Added doc
* Added function signature in PyOpenFLUID.py
* Modified header format
Added advise into 'DocString.cmake'
Added loadCSVOutput function

* Added doc to the function
* Added the function in PyOpenFLUID.py