Feature/compression support

Heroku does not support gzip in the routing mesh, leaving it to the applications to implement compression. This would typically be configured on the <Connector> element in server.xml. 

* Add --enableCompression flag
* If set, set compression "on", and configure "common-case" MIME types as compressable (HTML, plain text, JSON, JavaScript, and CSS).
* Other defaults left as-is (minimum size, sendFile support, etc.)