Make global autoplay setting

Use logic abstraction to start or stop updates for any graph type using a
pre-defined function name per type.

Simplify the autoplay button generation by making it a show/hide value instead
Extend util to define the stopButtonClick method
Extend query string manipulators for obliteration

Obl(iterate) removes the entire key from the query string.

Use new method to remove the play setting when changing timespan or graph type.
Format stacked.js, extend updateStacked() as separate function
Remove obliterate call in navbar_buttons

Doesn't actually obliterate, breaks all navbar buttons instead.
fix query hash chaining logic
Merge pull request #4 from anchor/autoplay

Autoplay global setting implementation