AddNodes functionality
Skeleton for extending model class to have
subclasses "student", "given", and "active"
Not tested yet.
Change pedagogical model -> pedagogical module.
Construct an example of how to do subclasses for model.
Solutions aren't the prettiest thing in the world, but
they work.
some Cosmetic changes on node editor
Merge branch 'master' of https://github.com/rptiwari/LaitsV3
Working example of subclasses for model.
Load (but not use) PM in main.  Perhaps it should be loaded
by the controller?
Small fix in draw-model.js so it starts up.
Adding changes to index.html
Merge branch 'master' of https://github.com/rptiwari/LaitsV3
changed calculations.js RenderGraph and RenderTable
Revert "some Cosmetic changes on node editor"

This reverts commit 39d1608c21540636408ced4be27c08a405da8e50.
Make PM called by controller, passing in the mode.
Start work on changing PM format.
addConnections function in drawmodel.js
Merge branch 'master' of https://github.com/rptiwari/LaitsV3
calculation.js and model.js added with switch functionality for student model and solution model
Change JSON format to have distinct id for given nodes
and student nodes.  Also, there should never be a case where a node id
is changed.  Also, use id to match student and given model
and label description choices.

Simplify if(expr === true) -> if(expr)

Work in progress on huge rewrite to PM.
Merge branch 'master' into sachin