Fix for build script - CoffeeScript compilation errors were being ignored.
Removed docs folder (no longer keeping generated artifacts in the repository).
Removed build folder (no longer keeping generated artifacts in the repository).
Updated .gitignore to reflect removal of generate build artifacts.
Rewrote Promise implementation for improved performance and to comply with the Promises/A+ 1.1 specification.

New Promise implementation derived from promise.coffee and promise-as3.
Updated to a manually browserified build of Promises/A+ 1.1 specification test suite (aka promise-aplus-tests 2.0.3).
(Patched the promise-aplus-tests 2.0.3 to work in PhantomJS.)
Added Deft.util.Function.isFunction (aka Deft.isFunction) as a workaround for broken Ext.isFunction implementation in Ext JS 4.2.0 and 4.2.1.

Fixes #123