Provide indication of stale platforms and ability to update them

[jsoref]

The refresh icon is derived from this public domain icon: http://publicdomainvectors.org/en/free-clipart/Eco-water-recycling-vector-icon/6856.html -- it's actually only inspired by, this art was drawn by me using InkScape

Closes #7

[rcruz]

Functions well. Just need to match appearance with the rest of the page: font color #565e66, border of button #cccccc, button hover background color #cccccc

[rcruz]

@bryanhiggins @kwallis When upgrading a platform is possible, do we want to encourage the user to update? I'm thinking a highlight color on the upgrade notification will help with this. Thoughts?

[kwallis]

How risky is an upgrade? How often would it require code changes? 

[jsoref]

@rcruz I think a highlight color is probably a good idea.

@kwallis within the WebWorks 1..2 cycle, we've occasionally messed up such that upgrading broke things (specifically Cordova's exec method is supposed to be async, but we had written a bunch of plugins that expected it to be sync, and when we fixed our exec to be async per spec, it broke all of our buggy plugins.) -- this was fixed before we shipped (well, for a weak definition of fixed).

OTOH, we also fixed a bunch of things for the 2.0 cycle such that in general an upgrade was a safe (to the best of our knowledge) action.

[bryanhiggins]

@kwallis The upgrade only affects the cordova-blackberry library, not the plugins, so it should never (or very rarely) require code changes. There is a story in the backlog to show plugins which have an update available.

[kwallis]

OK, let's highlight.