Added new ServeFile.js which allows to create response handler for static files. It is now used by hyperProxy helper functions. It should be possible to override video streaming now. File serving function can be overriden through the call to `hyperProxy.initHelperFunctions()` (see example in README).
Forgot to pass request.headers to filtering callback functions.
Fixed spelling/function call error.
Improved MIME test

Looks like node-mime module enforces invalid `font/opentype` MIME type, so let's output additional information, why failing that part of test may be OK.
Merge pull request #24 from ahwayakchih/master

Improved file serving.