Update Dygraphs to v2.0.0 (and implement zoom changes)

[icasdri]

Dygraphs has released version v2.0.0 with breaking changes that breaks how we currently implement Pin Value Range and Base Time Interval.

New behavior recommendations:

• Unzoom (via double click) will always unzoom out to full data in Base Time Interval
• Vertical-only zooms should not affect incoming live data
• Horizontal-only zooms with the right-most date "near" the current date should not affect incoming live data
• Only horizontal-only zooms with the right-most date "far" from the current date should have the view frozen from incoming live data
• Remove Pin Value Range (as vertical-only zooms will now effectively achieve this)
• Reinstate zoom animations (as they should work without the glitchiness now)