- Revised the #importing dependency structure. None of the BTIKit files import BTIKit.h anymore, only specific files they may need.
- Started using @import syntax for system libraries.
- All .h files are importing the specific libraries they need, rather than depending on global import.
- Removed .pch file from sample project to reflect standard deployment with Xcode 6.
- Moved macros to BTIMacros.h, so that they can be used, if desired, without importing the entirety of BTIKit.