Polychromatic v1.0.1

**Fixes**
- Removes compatibility for releases older than Xcode 5.1. Closes #13.
- Prevents crashes when the target is changed. Fixes #14, closes #20. 
- Sample themes are now installed even if the themes directory is not present. Fixes #19.
- Hard-coded Xcode app path strings are replaced with environment variables. Closes #15.