Move the packages out of backend and into the project root.
Pull the package and key code into their own packages.
Fix the frontends to use the keys package.
Run the tests on all the frontends.
Test removing a window from the middle of the stack.
Revert "Run the tests on all the frontends."

This reverts commit d7c6497e7c7c0081b23d4e4c554b79d709be765d.
Close some things when we're done with them in the editor tests.
Don't break the docs.
Merge branch 'move_packages'

Conflicts:
	backend/editor_test.go
Tidy up more resources during the tests.
Don't generate a python api for View.ExpandByClass.

We have a manually written one already.
Combine open_file.go with file.go.
Refactor some tests.
Refactor the find tests.
Refactor and close views and windows in some more tests.