Publish UMD bundle to flight-umd

[necolas]

Fix #210

This adds the umd bundle (minified too) to the flight-umd repo when you make release. This should also allow us to migrate to commonjs in this repo without a major version bump.

Pre-merge tasks:

• Ensure README and example tweaks #293 and Small chores #294 have been merged.
• Add all existing tagged releases starting from 1.0.0 to flight-umd. Reference: https://github.com/flightjs/flight/tags
• Relevant README updates.

Post-merge tasks:

• Unregister 'flight' on bower, re-register using flight-umd git endpoint: Unregister package requests bower/bower#120

[necolas]

Closing. Will leave the branch in place if there's interest in picking it up in the future.