Add support for inlining font files.

- Strip any query strings or hashes from url filename
- Add fontPath option
- Set correct mime type according to font filetype

The only edge case is for SVG files, which can be images or fonts. As of now, the plugin will continue to look for SVG files in the imagePath.
Decouple mime types from extension, refine font file detection
Check for existence of files, handle ambiguous nature of SVGs
Merge pull request #1 from smt/feature/font-support

Add support for inlining font files.