Feature/xctest

I replaced SenTest with XCTest. 
I cleaned up the FRAMEWORK_SEARCH_PATHS to not to contain some junk, please reference https://github.com/seivan/CocoaSPDY/compare/twitter:develop...feature%2Fxctest?expand=1#diff-607867dba70c420bf87de2f213acf3afR761

I changed the deployment target to 7 for making sure the XCTest run.

However, I can't seem to get the actual tests to run. I just get an exit with 0, which means it does run the library but that's the end of it. It doesn't actually run the suite, care to throw some eyes on this?


This also brings up the point I had earlier, of switching out static framework for using mainly Cocoapods or submodules for the source files.

I do have a suggestion for a better workflow by using local paths with cocoapods (it doesn't require cocoapods per say) but you can use it to work with the library and test things out easier, it also makes it easier to run tests as well as testing stuff out. 

Let me know if you're interest and I'll do a pull request or a fork with my suggestion and you can give it a shot, I really think spreading pre-built frameworks like this is an anti-pattern to open source. 

The benefits of spreading source outweighs the static pre-built frameworks.