Refactor

[camilleanne]

To do:

Transition the guts of pulse into a browserified node application. v1 (operates with just the green channel):

• [ ] transition from flask to node app
• [ ] modularize front end (move to a new repo)
  • [ ] make data filter configurable
• [ ] tests

v2 (uses ICA on all channels):

• [ ] implement or find a js implementation of ICA
• [ ] use ndarray
• [ ] more tests