getNewAddresses new signature

[Cylix]

From #304 (iota.lib.js changes):

total, returnAll & checksum options of getNewAddress are deprecated
Reason is responsibility overload & goal is to have getNewAddress() do only one thing, what the name says. Next step is to have it work with local store and accept seed as the only argument.

We already do not have checksum as it is moved to the Address model. For returnAll, makes sense to remove it, this parameter does not bring much benefit and make API more complex. For total, I am not sure about why removing it, probably leaving it optional should be fine as well?

[chrisdukakis]

if it's getNewAddresses is totally fine :D