Highlighting TODOs, FIXMEs, ERRORs

I found krakendev's idea quite interesting.

There are two downsides:

• it will highlight all ERRORs, even in this case:

NSLog(@"ERROR: Reason here");

• it will highlight code inside frameworks as well.

Sadly, I'm not good with bash, so I don't really know how to improve these downsides, but you might find it helpful, nonetheless. Keeping it for future reference, as well.