Implement proxy for `dom/*` using the new `sig/setup` and `sig/teardown` introduced in troopjs/troopjs-core#142.

Refactor `sig/initialize` and `sig/start` to use `when.map`.
Rename `$HANDLER` to `PROXY`.

Remove `CONSTANTS`.

Make it IE friendly via `.charAt`

Use `STAR` constant.

Named some methods, did some renames.