Merge pull request #194 from candrews/patch-1

Use animal-sniffer to ensure only Java 1.5 is used
Correct specialized platform name to Java6.

Also correct end-of-method fallback logic to not check for the presence of the MTU method, it will never be null when code is reached.
Merge pull request #197 from square/jw/stay-dead

Correct specialized platform name to Java6.
Add an implementation of URLStreamHandlerFactory