Maintenance

 - minor README improvements
 - update package dependencies
 - fix tests failing on Travis & Node v0.11 due to a race condition
 - fix #411
This is only removing a badge that was more often than not misleading.

You can run `npm outdated --depth 0` to find out which dependencies should be updated. Also by using `^` in version specifiers, we don't have to update package.json that often.