Also make sure to generate previews for .can files.
OS X makes some decisions about how thumbnails are displayed using the file UTI. By stating that these formats conform to `public.plain-text` instead of just `public.text`, OS X will display the file extension as a 'badge' over the thumbnail. UTI declarations within installed apps will override any declarations within Quick Look generators, so if users have apps with conflicting information, the badge may not display.
Open Babel is used to generate an SVG representation from the file contents, which is rendered in a WebView, which is drawn onto an NSGraphicsContext.
Common.m now has PreviewURL function for generating preview HTML, and ThumbnailURL function for generating thumbnail SVG.
Add support for SMILES and InChI formats
Use the Open Babel `gen2d` option to generate 2D coordinates for files containing SMILES and InChI formats.
If a CFURLRef is created and then cast to an NSURL, the CFURLRef needs to be released. This is done through a `__bridge_transfer` which tells ARC to release it for us.
Added some more formats that Open Babel is able to read, and added some alternative file extensions and mime-types for existing formats.
Not quite there yet - the display code is commented out.