Feature request: Logging improvements

[akphi]

The only logger we have right now is the browser console, which is not the most convenient as it requires user to use a feature from the browser. Instead, we should try to make use of our in-app console.

Implementation

• Use xterm for logging
• Have a logger interface (this needs more thinking but we can roughly think of the followings):
  • ConsoleLog which prints to the web console - IMPORTANT Also, use this in test and disable the rest. Right now, some errors are not printed out to console during test, making it hard to debug.
  • GraphLog just for graph processing
  • AppLog for other events in the app
  • Configure the channels for each log, e.g. AppLog and GraphLog will cover different channels
• CONSIDER moving logger into the app initialization interface
• CONSIDER have an interactive log to allow user interacting with the app in a super hacky mode :)