Add ability to specify template extension (Author: jaketrent)

Original: https://github.com/niftylettuce/express-cdn/commit/a8fb28a1d2c270c14e5ee559fb0bc08ebe5cd9b6
Full support for Automatic parsing of background, background-image, content and src in stylesheets.

Now files in url() can have relative paths.
Full support for Automatic parsing of background, background-image, content and src in stylesheets.

Now files in url() can have relative paths.
Merge pull request #1 from danielsantiago/RelativePath

Relative path
Update knox version

Fix problem with this issue: https://github.com/LearnBoost/knox/issues/153
Update code to work with knox 0.8.x
Remove "readCss", remove timestamp from s3 file.
Fix absolute paths
Assets have absolute path now when compiling
Don't pass image/gif in optipng
Compare local file modification to S3
Update some dependencies versions
Add: Option to disable walk, useful to only walk with one worken when using cluster.
Remove break line that cause problem with "raw" tags and add "image/x-icon" mime type as basic image
Merge pull request #49 from danielsantiago/master

Add ability to specify template extension (Author: jaketrent)