FIX PR #35:  Add basic keychain support

fixes up https://github.com/calabash/calabash-ios-server/pull/35

@jgallagher <== thanks!

- [ ] @krukow review
- [ ] add briar testing details
- [ ] add ruby smoke testing details
- [ ] add XTC testing details

very close now.  green lights locally on XTC for Briar and LPSimpleExample w/o linking Security.framework.



![2014-03-07_12-08-11](https://f.cloud.github.com/assets/466104/2356397/4761b00c-a5ec-11e3-9b68-37bc6188fbe5.png)