Ipns name resolution

This branch is not yet complete, but before i move forward, the name resolution code (in namesys) needs some critiquing. There are also a decent number of bugfixes in this branch that i ran into while trying to get the code to a point where i could test ipns.
Oh but, this will be sketchy, because if I `ipfs add` underneath you, this cached object won't reflect it, right? maybe TRTTD is to add the caching inside ipfs core, no?