Release Liquid 0.7.0-beta

## 0.7.0-beta: iOS 5 Support + Minor issues

* [feature] iOS 5 is now supported.
* [feature] Added a new method for SDK integration: Liquid Xcode Project. Don't forget to add `-all_load` and `-ObjC` to "Other Linker Flags" at **Build Settings** in your project.
* [feature] Invalid characters on attributes and invalid event names now raise a NSAssert message
* [enhancement] Many performance improvements on HTTP requests queue
* [enhancement] `CLLocation` information is now sent to Device entity, and not User entity
* [deprecate] `identifyUserWithIdentifier:attributes:location:` -> Use `identifyUserWithIdentifier:attributes:` instead, and `setCurrentLocation:` in separate methods.
* [deprecate] `setUserLocation:` -> Use `setCurrentLocation:` instead
* [fix] Fixes a bug that could crash the app when the app is open and closed very fast
* [fix] HTTP queue is now a circular queue (FIFO), privileging most recent events