Started working on some of the HTTPUtils and AsyncHTTPUtils stuff

Added HTTPStatusCodes for obvious reasons
Added Pair<F, S> just because it may be useful in the future
Added FileGetTask for AsyncHTTPUtils to get a File from a URL and save
it to a Directory
Continued working on Async HTTP stuff

Added stubs in AsyncHTTPUtils for getting files
Added methods to get a HTTPStatusCode from an URLConnection and a
HttpURLConnection

Changed HTTPStatusCodes to HTTPStatusCode

Finished FileGetTask (not tested)
Added Joe Desbonnet's JBDiff library (0.1.1)

Patched it with Veikko Werner's patches.
(http://sourceforge.net/p/jbdiff/home/Home/)

TODO: Make more efficient.
-- Maybe use Java 7's Channels Object? Need to run tests