New version of rx

- ref: Fixes a memory bug probably rooted in a clang optimization that occurs when compiling with the clang that comes with Xcode 6 beta4 for x86-32
- func: Workaround for a bug when building for 32-bit iOS
- target: Better RTTI and Exception feature testing
- state: Added clear() method to State
- netreach: New! NetReachability can be used to observe reachability of exernal networked peers. Currently only supports iOS and OS X.
- text: New! Unicode text tools (folding/normalization, trimming, predefined charsets, etc)
- Uses C++11 "using" type aliases instead of typedef