Exteneded features to support RZVinyl

@Raizlabs/maintainers-ios 
These are some extended features to support RZVinyl, since it needs to make use of some of the internals. I tried to keep the private stuff clearly marked as such, and the podspec specifies exclusion of the private headers as well.

#### TODO:

- [ ] #6 Document README with cocoapods installation instructions.
- [ ] #7 Prepare podpec for release

**Note:** This is intended to be a living pull request until this is vetted and all the TODOs above are addressed.
Are there system defines for these? Otherwise it seems silly to create preproc definitions for single characters.

I'm recalling `#define kSeven 7` from a certain client's codebase.