Easy JSHint cleanup

Did a pass of all of our javascript with JSHint, and cleaned up missing semicolons and strict equality suggestions it pointed out.

I did not deal with any other issues, of which there were many, and I didn't touch any of the `tiny_mce` javascript because we didn't write it. 
Actually it should only check `null` and should not check an empty string. Inside the `if` statement it is reading the value.