Bugfixes, style fixes and memory leak fixes

- Added initWithCoder: method to SMFancyText.
- Split SMFancyTextElement into separate file.
- SMFancyText delegate method receives a pointer to the originating object.
- Modernised #pragmas.
- Removed unnecessary property synthesizers.
- Removed unnecessary private method signatures.
- Replaced property calls in init and dealloc methods with calls to ivars.
- All memory is correctly released.
- Fixed compiler warnings about mismatched type comparisons.
- Fixed compiler warnings about switched enum values.
- Tidied up formatting.
- Fixed newline warnings.
- Added default retina image.