Add ol.coordinate.format function

Return a formatted coordinate. Example usage:
  > ol.coordinate.format([0.01 ,12.14], "{x}, {y}", 2)
  "0.01, 12.14"
  > ol.coordinate.format([0.01 ,12.14], "lat: {y} / lon: {x}", 1)
  "lat: 12.1 / lon: 0.0"
Remove opt_precision check in ol.coordinate.format

Default is already 0, see http://www.ecma-international.org/ecma-262/5.1/#sec-15.7.4.5
Better ol.coordinate.* documentation
Add jsdoc plugin that maps @todo tags to @stability and @observable tags.

This is a temporary measure until Plovr handles custom tags or is replaced in the build system.

Add support for indicating API stability with inline documentation

In preparation for documenting the stability of API features, this commit adds support for indicating API stability via a new jsdoc tag @stability.  There is a small plugin for jsdoc that adds a new tag, @stabiility, with some ability to enforce specific level names.  The templates and css have been updated to include the stability level in the generated documentation. (+1 squashed commit)
Squashed commits:
[d6bc03d] Add jsdoc plugin for documenting observable properties of a class.
Merge pull request #1180 from pagameba/doc-jsdoc-plugins

Add jsdoc plugins for stability and observables.
Fix `@todo observable` name reference.
Remove unnecessary Get column from observables
Merge pull request #1187 from pagameba/fix-todo-observables

Fix todo observables.
Merge pull request #1185 from fredj/coord_format

Add ol.coordinate.format function
Quote values in apidoc
Fix bottom left and top right computation in moveend example
Merge pull request #1189 from fredj/apidoc

Minor apidoc updates
Merge pull request #1182 from fredj/moveend_example

Wrong extent coordinate order in moveend example
Add parsing of LinearRing and the display of a GeometryCollection
Fix get feature info for Geometrycollection
Remove comment
Remove PointLiteral equals function
Add a 2nd paramter to createLiteral function