Always build the YARP_manager library as STATIC

This is a temporary fix, the library should use a YARP_manager_API
macro for __declspec(dllimport/dllexport) on windows
[OS/SystemInfo] added environment info to platform information (TODO: actually retrieve that info)
added --which flag to yarprun to retrieve remote location of script files from yarpmanager's scriptBroker
[OS/SystemInfo] retrieve environment variables on host machine