No markup in shortdesc

The example parser and index template don't handle markup in the shortdesc element.  Use the docs element instead.
Strip tags from shortdesc (et al.) when parsing

This strips markup from elements with id attributes that we care about: title, shortdesc, tags.  This will only work for people who use `npm install && npm start` to browse examples.  The other example parser doesn't strip this markup, so it should still not be used in these elements.
Merge pull request #1952 from tschaub/shortdesc

No markup in shortdesc.
Test canvas size with an untainted canvas
Do not shrink test canvas
Make comment about shrinking the canvas more descriptive
Merge pull request #1956 from ahocevar/shrink-comment

Make comment about shrinking the canvas more descriptive
Use ol.dom.createCanvasContext2D and remove canvas variable
Merge pull request #1955 from ahocevar/canvas-no-taint

Test canvas size with an untainted canvas
Change renderer order in getRendererFromQueryString

To order should be the same as ol.DEFAULT_RENDERER_HINTS.
See #887
Merge pull request #1958 from fredj/renderer-order

Change renderer order in getRendererFromQueryString
Set shouldStopEvent to identity in DragBox

This fixes a bug where the map is panned when boxes are drawn.
Use goog.functions.identity where it makes sense
Merge pull request #1960 from elemoine/stopevent

Implement shouldStopEvent in DragBox interaction
Define ol.pointer.PointerEvent.createMouseEvent before using it

Fixes #1961
Merge pull request #1962 from fredj/1961

Define ol.pointer.PointerEvent.createMouseEvent before using it
Use externs/olx.js instead of objectliterals.jsdoc

The single externs/olx.js file describes all of the "options" objects we accept in our constructors.  The @typedef annotations are used by the compiler for type checking.  The @type annotations include documentation for individual options and serve as externs when compiling a profile of the library.  When compiling an application together with the library, the externs/olx.js file is included as one of the sources to provide the @typedef's without generating externs.

If we want to maintain multiple src/*.externs.js files instead of one large externs/olx.js file, we can.  But while we are still using Plovr, it makes for easier build configurations to have one file.

This removes the build tasks that generated the build/src/external/src/externs/types.js and build/src/internal/src/types.js files as those are both replaced by the single externs/olx.js file.
Unused externs and typedef generating code