add drop down menu for commands

[firezym]

1. add button (original split cell extension style) and a drop down menu for commands using menu of lumino widgets
2. optimize the desription for commands

Already test it by uninstalling and re-installing from git remote repo as a clean start. Pls check and test it further.

[firezym]

Totally no clue what's wrong. It worked fine in my env. Please help to check and feel free to change anything by commit @parmentelat

[parmentelat]

just run jlpm run lint and commit any change

[firezym]

Passed the check and seems ok now.

[parmentelat]

thanks, will issue a new release shortly

[parmentelat]

0.1.4 is up at pypi !

[parmentelat]

and fyi in just released 0.1.5 one can turn the button off or on through the settings editor

[firezym]

Cool !

[parmentelat]

it took me some trial and error cycles to finally get it right wrt multiple notebooks opened at the same time
(the settings business was far from crucial, I'm just using this as an opportunity to deepen my knowledge about jlab extensions)

hopefully version 0.2.1 should be quite fine now, please try to shake it up as much as you can :-)

I know of one remaining issue #7, so if you see it and can help pinpoint how to reproduce, please comment on that one