Ryantam626-jupyterlab-vim

* Update for JupyterLab 0.35

* Update for JupyterLab 0.34 (57) Thanks MisterVulcan

* Update for JupyterLab 0.33 (52) Thanks ah-

* Requires JupyterLab 0.32 (Beta 2)
* ctrl-g shows function signature (36)

* center cell command (33)
* `-` splits cell in vim command mode (33)
* ctrl-c copies instead of leaving insert mode if you aren't on a mac (34)

* add moving cell commands
* Add delete/yank/paste cell commands (28)
* select first and last cell shortcuts (24)
* change to focus selector to fix debug prompt select