Detect and flag static mustaches (Ref #493)
Fix mustache content converter - unintentional global var
Fix mustache converter - no Array.find, and didn't dig into [0] for delimiters
Fix old tests that were using '[[' and '[[['
Add a couple static parse tests
Add static check to mustache resolve
Merge remote-tracking branch 'origin/dev' into static-mustachio
Move isStatic check to viewmodel
Add test for static interpolator
conflict resolution
Merge pull request #819 from ractivejs/static-mustachio

Thanks @jrajav - merging this in.

It's a *little* dirty, insofar as the viewmodel should probably ideally know nothing about the things that depend on it. But that's already not the case (e.g. it has a reference to `this.ractive`), so for the time being I vote we let it slide - the important thing is it has test coverage, so we can do things the 'right' way (i.e. only registering/unregistering where appropriate) later.

Also: I've finished mucking about with `ReferenceExpressionResolver` and `ExpressionResolver` for the time being ;-)