Revert "Tabs to spaces!"

This reverts commit 83fc3f718ada88f29f882ccca89443590bb56a54.

This made CoffeeLint even more angry, I used 4 spaces instead of 2...
Exchange tabs for *2* spaces.
Remove unneeded brackets from `require` statements.
"#{}" should be used for string concat instead of "+" in CoffeeScript.
Merge branch 'tidy-up'