Handle observables and fires augments in plugins

This makes it easier to switch themes.
Merge pull request #2042 from elemoine/circle

Use correct circle canvas size
Document ol.Pixel
Fix indentation
Document raw geometry types
Switch to the Jaguar theme

In addition to a nicer layout, this adds a searchable sidebar
and a source code viewer.
Better readable color for type links
Set snapToPixel defaut value to true
Avoid defining default values at multiple locations
Better match the ol3 color theme
Merge pull request #2043 from ahocevar/nicer-api-docs

Nicer API docs
Set snapToPixel to false in dynamic-data example
Remove duplicate record field "duration" in olx.js
Merge pull request #2048 from elemoine/duplicate

Remove duplicate record field "duration" in olx.js
Fix anchor offsets for line numbers
Merge pull request #2049 from ahocevar/anchor-line-numbers

Fix anchor offsets for line numbers
Merge pull request #2047 from elemoine/snaptopixel

Set snapToPixel to true by default
Export ol.BrowserFeature.HAS_WEBGL
Merge pull request #2050 from fredj/has_webgl

Export ol.BrowserFeature.HAS_WEBGL
Lower case the event name