fix #550 reorder some tests

Change order of the tests so the long ones do not block the whole campaign
at the end. Speeds up the whole campaign by ~20s (from 2m10s to 1m49 on my
machine) on 8 CPUs.

Related to #538.
refactor Drag tests

1. Removed tolerance which was hiding problems in IE8 and changed the test
environment (increased border size to 15px) to underline the problems in IE8
2. assertTrue etc. -> assertEquals
3. Extracted abstract class to handle shared code
4. Renamed files to follow the unwritten convention that Test means an
executable test, while TestCase - abstract shared class

Close #544.
fix #568 Wrong animation callend in slide transition 3d

The slide transition was adding different animation when the slide transition was called using the 3d version. Now it uses the same ease-out animation.
refactor whitespace formatting
feat #445 leading tabs detection in the code

A grunt task is added to prevent checking in unformatted files
in the future. It's very simple now, just checks for leading
whitespace being a tab instead of a space.

Close #445.