Created new NPM package `peerinstruction`

Moved files from `./client` to `./peerinstruction/public`.

Reworked `server/load.js` and `server/logic.js` to work as application
starters.

Next to do: change views to use Jade engine.
Removed NPM package, admin~>instructor, some UI tweaks

I started preparing JS code for broadcasting
Introducing instructor's broadcasting mode. With bugs.
Fixing "../app.js" ~> "/app.js" within HTML templates
Fixing students mode (split mode)
PubSub architecture: testing first events

I'm now testing this architecture to check if these events are
propagated correctly:
* new_student
* student_gone
* new_instructor
* instructor_gone

So far it works nicely.  Additionally I have to keep the list of
students and instructors on the server and publish an RPC for newcomers
to get the actual lists.
Unified JavaScript codebase (one file: `application.js`)
New RPC commands to get students and instructors lists
Moved subscription events to named on_* functions
Splitting students into rooms now works!
Changing mode with buttons now works!
Now the code reacts on mode change in every instructor client
Student dashboard: show students in the same room (after split)
Basic framework for PeerJS connections started

Needs more polishing to actually work with broadcast mode and groups
mode.
Moved *.js files to client_pubsub/javascript, new index.html
Broadcasting mode: instructor's stream works

I'll add group split mode and then hunt for bugs. That's the plan.
Broadcasting AND split mode BOTH WORK!!!
Added some TODOs
Merge pull request #1 from pbanaszkiewicz/pubsub_arch

Pub/Sub architecture