FilePaths in project setting can be absolute path or relative to rproj's directory.
fix a crash bug when exiting rockete with file opened.
FilePaths in project setting can be absolute path or relative to rproj's directory.
Merge branch 'Branch_968541f36e6be5f27bf43b8b26dd51b49df1f087'

Conflicts:
	src/ProjectManager.cpp
Merge pull request #56 from harmy/master

fix a crash bug when exiting rockete;better support for relative path in rproj file.