Move deviceID initialization to MonoBehavior Start

This was required on my system because field initializers are called from the loading thread during scene loading, but deviceUniqueIdentifier must always be gotten from the main thread.
Removed three classes' MonoBehavior inheritance

I'm not as sure about this one, so Duane or anyone feel free to point
out my error.  Are we sure that Request, Response, and ProblemWorker
should inherit from MonoBehavior?  They do not seem to use any of the
superclass features, and they are not intended to be script components.
Removing the inheritance lets us instantiate them with the "new" keyword
without getting warnings from the MonoBehavior class.
Basic menu functionality and (broken) messages

I added some basic menu functionality via some scripts and prefabs.  I
also created two two messages and have the protobuf changes from Duane.
But the messages aren't working yet.
Controller tests registration and verification

When the unity scene is loaded, the SenseixController will test device
registration and game verification.  game verification isn't working
yet.
Added easy-to-use interface

Just for my own convenience and to see if we like it, I've created a
class outside the senseix namespace called "SenseixPlugin."  But it
might be redundant with SenseixController.  I'm open to input, thanks!
Small changes moving toward leaderboard

The leaderboard view will, I'm thinking right now, use the PlayerData
list which is stored in SenseixController after pulling.  Still at work
on this!
Simple leaderboard implemented

Menu improvements, primarily a simple leaderboard.  When I tested it
with data I generated myself, it worked swimmingly.  However, there
might be subtle variations in the server data that cause bugs.  Overall
feeling pretty good about this commit though!
Added menu prefab

Forgot I didn't have this in yet - pretty important!  All the menus I
have so far.
Menu improvements.

Most menu features are there.  Including student selection, leaderboard,
device/acount linking, and visits to external URLs.  However, some
messages required by the menus still fail.   By the way I love Unity's
new UI system soooooooooooooooo much!!
Added summary comments in the SenseixPlugin class

For completeness, to help potential readers of the code and users of the
class.
cleanup files no longer required in the plugin
Continued work on integration of menu with messaging

Student switching now displays the true list of students - but player
registration is still not successful.  Leaderboard has some messaging
but is untested.  Things are moving along!
Updated prefab

Almost forgot!
Made disable other uis more intuitive

Now this will reenable everything it disabled without bothering the
client
temporary commit to get to be able to pull problems, Duane to fix the problem logic
Leaderboard and StudentSelection. Staticization.

The Leaderboard and Student selection functions are now (fingers
crossed) working with the server!  ProblemWorker and Sequest are now
static.  Score reporting is also implemented, and some int playerIDs
which should have been strings have been corrected.  Also, the
missingscript bug with the prefab and the double initialization bugs
have been ironed out in my environment- but I'm not sure about Unity
5.0.  Cool stuff!
Code cleanup

The SenseixPlugin was an implicit singleton so I made it an explicit
singleton.  Changed messages to return boolean representing success as
per C# convention, instead of integer represent success.  Also a small
fix in StudentSelection.
add support for custom mime-type protobufs
sign out.  namespace changes due to protobufs.

Our protobufs namespaces changed, and therefore the namespace of the
plugin needed to change.  That's the weird part.  But the good part is
that I got the new field from the server!! yay!! also, sign out is very
close.  Just need to address a 404.
Added unity package to control system

With this package, clients will be able to successfully use our
prefabbing SenseiX menu. :)