Partial removal of Circular parameters dependency

The intent of this pull request is clear from the IRC discussion, but some things to note are that in this PR we have lost the 'generic' form of a `Curve` in that it is now specific to `ECC` by having the curve parameters necessary for construction.  This was technically already necessary, but was hidden behind small hacks like the `tacked on` `params` variable in `names.js`.

Like the other PR, this is API breaking.