start of work on 3.6
#749 - make addFiles API method easier to use cross-browser
#803 - stamp version in header
#803 - additionalFiles don't need to be copied from temp dir
check for styles.opacity being undefined in qq.css

credit goes to this answer: http://stackoverflow.com/a/15505748
#803 - version number in log messages and header
Merge branch 'feature/803-embed-version' into develop
use less strict not null check
Merge pull request #817 from hulbert/develop

check for styles.opacity being undefined in qq.css
#805 - start of promissory callback support - onSubmit
#805 - onCancel accepts promissory callbacks, qq.Promise can store multiple success/failure callbacks now
#805 - simply bind alternative (since all supported browsers don't implement bind and I don't like modifying Function.prototype)
#805 - why not call it bind?
#805 - document it
#805 - fix documentation error, and add some spacing
#805 - promissory onResume and onValidateBatch
#805 - promissory onValidate (respecting stopOnFirstInvalidFile)
#805 - promissory onSubmitDelete
#805 - accidentally removed call to onSubmitted callback
#805 - document onPasteReceived as promissory, allow additional params to be passed to onSuccess callbacks