Proper Linting

I made a few quick changes to backbone.layoutmanager so it lints properly according to my handy-dandy SublimeLinter.

The main changes are visible in the diff, but in essence:

1. Swapping of == in place of === or _.isNull() when needed
2. Removal of "returning assignments" and "expected condition, saw assignment"
3. Removal of trailing whitespace

Tests are passing just as in the master, all but one test in dom.js.