nion15update

[ltizei]

The major change was to the init(self, file_path) method. If I understand correctly this:
'''
else:
r = Profile.FolderProjectReference()
r.project_folder_path = file_path
'''
should take care of older libraries, but it does not seem to work. When ran with a valid nion library path, it does not raise an error, but the associated project in r.project has .data_items empty.

Otherwise, it works for nionswift=0.15.1 projects.

[ltizei]

I made a mistake, I was trying to merge my branches in my repository.

[francisco-dlp]

Thanks @ltizei! I'll merge this as-is and merge a follow-up #5 just after. Sorry that it has taken me so long to come back to this.