Make extensions work with non-root NBGallery

WIP: Porting 1.0.6 changes to 3.x (#54)

* WIP: Porting 1.0.6 changes to 3.x

* Version number changes, fixing some minor bugs

* Fix mistake in upload

Make extensions work with non-root NBGallery

Back-port for early Lab 3 releases

Labv4+/Notebookv7+

Move launch point to jupyter_server rather than nbextensions (#52)

* Move launch point to jupyter_server rather than nbextensions
Closes #51

* fix juptyer_server dep to match lab

Migrate to Labv4/Notebookv7 entirely

Almost move post hack to the lab extensions

2.0.4

Diff view now works properly in Dark Mode in JupyterLab

2.0.0

Migration to Lab 3.6+, Lab 4, Notebook v7

1.0.1

This release rebuilds everything to work with Retrolab/Notebook v7 as well as JupyterLab and refactors the Gallery menu plugin to be a top-level menu rather than tool-bar buttons.

v0.3.0

Added support for tracking cell execution status/time

Updating the jupyter-nbgallery dependency

Now dependent on jupyter-nbgallery 2.0 rather than 1.1.1

Lab 3.0 support

First full release that supports Lab 3.0