Create build-header.py

Build header file from Font-Awesome/scss/_variables.scss
Make build-header.py executable.
Merge pull request #3.
Update IB files to Xcode 5 version.
Update schemes.
Update Podfile.
Update travis-ci config.
Update Font-Awesome to 4.0.3.
#4: Set rendering mode to original when setting color.
Update change log.