Extended functionality

- Re-wrote the plugin as a jQuery plugin
- Supports multiple instant

Following is a list of differences from the original version:
- Re-written to be a formal jQuery plugin
- You can now render multiple bibtex strings:
$("#block1").BibtexJS();
$("#block2").BibtexJS();
- Clean way to define the reference rendering template
- Contains default renderers so that if you want to just "get done with
it" like
including this script in your site requires one line of javascript :)
- Provides customization (e.g., you can include your name to highlight
along with  the formatting function)
- Detailed documentation on how to "hack" this plugin