Make _normal2Camel recurse as well

_camel2Normal would take a hashref as an argument, but I needed
hash keys to be able to go the other way as well.

At least it got less readable which appears to be a goal of this set of subs
Send rpc %args through _normal2Camel

Transmission likes things (specifically download-dir in my case) to have
dashes not underscores.

This fixes all the args up so you can generally use either.
Merge pull request #3 from afresh1/master

Transmission torrent-add RPC doesn't accept download_dir as an argument