Add run scripts

This branch adds 3 scripts, generated by CMake : 

* medInria.sh, to start medInria on UNIX, it sets MEDINRIA_PLUGIN_PATH, and takes into account PRIVATE_PLUGINS_DIRS if provided
* medInria.bat, for Win32, which starts medinria directly, after having set MEDINRIA_PLUGIN_PATH (again, with PRIVATE_PLUGINS_DIRS included if provided), and PATH, so DLLs are found
* medInria-dev.bat, for Win32, which opens the medinria project in Visual Studio, after having set the right env vars, so that the Run/Debug buttons work out of the box.

It's tested on linux and win32, please test and merge quickly, I documented in the wiki assuming they were available (no pressure ;) ).