Repo cleanup to comply with new catapult deploy process

- Added `/dist/` folder to `.gitignore`
- Replaced references to version number with `0.0.0`
- Replaced all-release `CHANGELOG.md` with per-release `changelog.txt`
- Removed `release.sh` script
- Added `npm run travis` command to `package.json` to build the
distribution files before testing
- Updated and corrected things in the README
- Updated README build badge to only show state of `master` branch
- Added header with version number, repo link, and license to all dist
files
Fixed incorrect link to signup page in README
Updated distribution file header
Updated included files in package.json and bower.json
Merge pull request #112 from firebase/jw-catapult

Repo cleanup to comply with new catapult deploy process