Release 1.1.1

@arrouse A bit of maintenance to get the nibless cell loading working. Instead of trying to catch the exception, it now just checks if the nib file exists, since as you probably noticed, the stupid `nibWithNibName:bundle:` method on `UINib` doesn't return `nil` if the nib does not exist (whose idea was that??).

Also made subspecs for the extensions. Let me know what you think.

Related to #15 

### Tasks

- [x] Code review
- [x] Tag "1.1.1"
- [ ] Push updated podspec