TODO for separate lib/vtd directory
View types are objects instead of classes

From now on, there will be only one VtdViewSummary object, and it lives from
when it's first created until vim exits.
For specific setUp/tearDown: delegate not override
saveCursor and restoreCursor VtdView functions

Save on teardown; restore after adding content.
Also save cursor before refresh, if view is active

This requires me to add concept of an 'active' view.  It's set to true on setup,
and false on teardown.
Contexts: stay on character right before word

Otherwise, the saved/restored cursor position causes apparent 'jumps', due to
interaction between 'conceal' and the length difference between, e.g., [@+foo]
and [@foo].
Show title of each view (with highlighted keymap)
Get TrustedSystem.Refresh()
Refresh system instead of clobbering it

Otherwise, if we set the Contexts, they'll be gone before we can request the
NextActions!
Don't conceal the +- from context names

Makes it more clear what the context statuses are (esp. if the colors don't
work).
Update TrustedSystem contexts when we change them
Add barebones NextActions view