Gsoc merge waypoints test

• Added popup for permission update and delete, fixed bug of buttons not disabling when permission is changed, added force close to view windows

• added tests for mscolab merge window and export/import, added tooltips for buttons

• Removed Native menubar from mss main window to improve UI for MacOS, fixes issue #554

I have been trying a lot to see what’s causing the error in the tests.
I am currently stuck on 2 things:

1. There is a git lock error which sometimes shows up in file import test

2. The merge dialog tests don’t work when the whole test suite is run but they work fine when run individually. I don’t know why this is happening as each test starts with a clean slate.