Improve handling of 'b', add beginning-of-line '^', add more movements to visual mode.
Implement more vim bindings and tweak kill/copy

- Handle [0-9]*G, gg, w, b, movements in visual mode
- Yank/delete the newline if visual (line) mode selection reaches the
end of a line
Merge pull request #7 from m4burns/master

Implement more vim bindings and tweak kill/copy