Merge pull request #1 from dfelinto/master

Small code refactoring by Dalai Felinto, no functional changes.
- Rename to "Jump to..", to match Jump to Marker, Jump to Keyframe, etc.
- Register operator so you can disable "Next" from the Last Operator panel, and undo.
- Obrigado Dalai for unstupidifying my code :)
Store missing keymap for unregistering, and small style cleanup