Bugfix release

• Compatibility with Bokeh 0.11
• Fix for interleaving %matplotline inline and holoviews plots (Issue #179)
• Major overhaul of website and notebook building making it much easier to test user contributions (Issue #180, PR #429)
• Matplotlib legend z-orders and updating fixed (Issue #304, Issue #305)
• color_index and size_index plot options support specifying dimension by name (Issue #391)
• Added Area Element type for drawing area under or between Curves. (PR #427)
• Added Columnar Data Tutorial and removed most of Pandas Conversions as it is now supported by the core.
• Fixed issues where slicing would remove styles applied to an Element. (Issue #423, PR #439)
• title_format plot option now supports {dimensions} formatter (PR #436)
• Major improvement for grid based layouts with varying aspects (PR #457)
• Compatibility with the latest Bokeh 0.11 release (PR #393)
• Major rewrite of the documentation (PR #401, PR #411)
• Improvements to Renderer API to allow JS and CSS requirements for exporting standalone widgets (PR #426)