code review:  iOS 7 style back button for iOS 5 + 6

IMPORTANT: this is not a request to merge, but a request for a code review

i am working on an iOS 7 treatment for one of my apps and I am trying to replicate the iOS 7 (navigation) bar button item in iOS 5 + 6.

working from the code in FlatKit, i was able to make a lot of progress, but i am stuck on a problem that my drawing and layout foo is not strong enough to solve.

i am wondering if someone (or several someone's) would be willing to do an old fashioned code review and work with me to solve this problem.

as you can see from the screenshot, i am having trouble with the borders of the button clipping the right-hand side of the text.  

i could move the text over to left and solve the problem for short titles like 'Back', but i would like a general solution (and one that matches the iOS 7 layout).

anyone interested in tackling this with me?

for debugging, i confined the changes to UIBarButtonItem.

![2013-07-31_23-22-22](https://f.cloud.github.com/assets/466104/890122/e952f0d6-fa2c-11e2-8f15-a0102176d725.png)