keep notes for ChimeraX

Seep either session-specific notes or notes across all sessions.

1. download the .whl file from the dist folder
2. in ChimeraX, run "toolshed install /path/to/ChimeraX_notes-version.whl"

The "My Notes" tool is under the general tools. Select text and click the "turn selected text into command link" button to turn the selected text into a ChimeraX command. When you click the link, it will run the command. Note that the command is set at the time this button is pressed, and it may not be editted later.