Projector: Inspector-panel neighbors slider editable

[francoisluus]

Make the neighbors slider editable in the inspector panel of the projector. This allows for finer-grained control on neighborhood size when selecting groups, which becomes important during interactive supervision.

Demo here: http://tensorserve.com:6021

git clone https://github.com/francoisluus/tensorboard-supervise.git
cd tensorboard-supervise
git checkout  de640f6fb3a4dd1822dafca928055e8f0476ddac
bazel run tensorboard -- --logdir /home/$USER/emnist-2000 --host 0.0.0.0 --port 6021

Design and behavior

1. Lowered maximum from 1000 to 999 to fit into slider edit box.
2. Requires [Enter] or unfocusing to set the new neighborhood size.
3. Edit box arrows auto-hide when unfocused.

Neighbors slider before

Neighbors slider with edit box

[dsmilkov]

Great. Thank you!