Don't fail when no featues are found in ol.format.TopoJSON
Add task for parsing examples
Merge pull request #1630 from tschaub/parse-examples

Add task for parsing examples.
Make ol.Map#isDef checking stricter
Assert that pixel is non-null when positioning overlay
Merge pull request #1609 from twpayne/stricter-map-defined

Stricter map defined
Merge pull request #1633 from twpayne/no-fail-in-topojson

Don't fail when no featues are found in ol.format.TopoJSON
Fix typo in text rendering
Merge pull request #1636 from twpayne/fix-text-bug

Fix typo in text rendering
Add a keyboardEventTarget option to the map

This option allows specifying the element to listen to keyboard events on.
Accept string for keyboardEventTarget option