lots of changes

* no longer allow automatic directory listings
* force Apache to server XML-related files with correct Content-Types
* add Expires header to static resources (images, javascript, css, etc.)
* rename incoming Range header to X-Range, so Apache no longer slices up responses which may already be range-sliced and/or transfer-encoded
added Request#ranges() function

-- Gets a list of Range byte-ranges,

Also fixed some logic in the other specific header parsing functions (#content_types, etc.)
added Range header support

also some comment changes
added support for Range and Accept-Range headers

closes #6

Also changed compression system to take header overhead into account before applying a compression scheme.
incremented version to 1.1