Improving iOS 7 bubbles, eliminate 2 compiler warnings, disable datadetectors in simulator

I adjusted the bubble-min images to have corner radii more closely matching iOS 7’s, and attempted to get them a bit sharper looking. Adjustments made to insets to sharpen up the appearance of the bubble on the top/right edges. Adjusted x and y position of the textview frame to improve padding and position text more closely to vertical center (this part’s kind of a hack… probably a better way than just hard-coding +4 and +3!) Here's a before/after gif:

![output_jpbcty](https://f.cloud.github.com/assets/127062/1798678/af76b8da-6b64-11e3-884f-94a962e7a33d.gif)

(BTW, am I crazy, or does the text seem a bit 'soft', especially the white text on blue bubbles?)

Eliminated a couple of compiler warnings I was receiving, one of which was due to compiling for 64-bit. 

Disabled data detectors when running in the Simulator, as this seems to crash with EXC_BAD_ACCESS quite a bit.

BTW, thanks for building this. :+1: