Fixin quirks

[heyitsgarrett]

This commit fixes #13 + #14:

• Handles enter key press in cases where no result is highlighted
• Adds an optional loading property to the Geocoder. This attaches a .loading class to the results list ul and leaves it to the user to decide what to do with it. I played with an additional div or attaching it to the input class, but this allows for the most flexibility.
• Newest versions of React also don't require the line /** @jsx React.DOM */ declaration, so I've removed that from the example code.

@yhahn -- would love your eyes on this before merge.

[heyitsgarrett]

Few more tweaks:

• set focus on enter keypress
• set focus when clicking result
• keep focus on input when clicking result