Examine.VCFTable :: -> :
Fix and update tests

Increased pdiff timeout to 30 seconds because 15 wasn't long enough on
my beleaguered MacBook Air.
Merge pull request #311 from hammerlab/double-to-single-column

Examine.VCFTable :: -> :
QueryLanguage.toString + tests
QueryLanguage.isEquivalent + tests
update CQL box in response to query changes
Add filter screenshot & update screenshots
address code review comments
move hasInitialized out of state
sort arrows reflect multiple sort bys
remove hasInitialized
update screenshots after rebasing
remove refs.input checks