Add default rake task which runs the script.

This is effectively the same as `bundle exec bin/github-watched`.
I like symbols.
Add gem-release for `gem bump` and `gem release`.
Rename lib/ files from "github-watched" to "github_watched".
Ensure any config names are escaped.
Remove need for "def self.foo".
GitHub requires User-Agent to be provided
Use RubyGems over SSL
Revert "Add gem-release for `gem bump` and `gem release`."

These don't work very well. Let's just use what bundler gives us.

This reverts commit 82598ed9ef9e226c2b1bac14fb188a9c946a311e.
Bump version