Fix Timezone Issues in Data Importing

- Update default date formatting string to interpret timezone data.
- Set date formatter to use GMT when a custom date format is used for date strings which don't include timezone.
Merge branch 'develop' of github.com:collindonnell/MagicalRecord into develop
Convert unit tests to XCTest, and clean up project to remove duplication of settings across targets
Latest Specta, and use my Expecta repo/branch for Xcode 5.x compatibility for now.
Use the compiler’s default language standards
Update installation documentation
Enable support for passing nil to +createInContext:
Merge pull request #549 from collindonnell/develop

Fix timezone issues in data imports
Restore tests - not everything is passing yet
Remove commented out code
Use firstObject
Fix all tests — hooray!