Usage example code updated

My changes to the project were mostly Android specific. I didn't want to include Apache commons libraries in my project, so I wrote manually those few functions from StringUtils and IOUtils and so on. Same thing with the slf4j logger, I converted it to use Android's built in logger. You had also UDT protocl supported, but it requested some external files so I commented those out since I didn't need to support UDT.

For some reason line 768 in ProxyToServerConnection.java didn't know class VerifiedAddressFactory, so I needed to comment that out. Something to do with DnsSec.

But here's the fixed README. 
1. filterRequest without ChannelHandlerContext parameter wasn't never called.
2. If filterRequest returns null, it produces a NPE in ClientToProxyConnection.java line 197.
3. HttpFiltersAdapter responsePre and responsePost should return HttpObject.