Mark parts of control and overlay as stable
Fix ol.BrowserFeature.HAS_TOUCH detection code

Use goog.global instead goog.global.document.documentElement to avoid
false negative results when using the chrome development tools (Touch
Events emulation).

Code borrowed from https://github.com/Modernizr/Modernizr/blob/master/feature-detects/touchevents.js
except for the DocumentTouch part which is deprecated (https://developer.mozilla.org/en-US/docs/Web/API/DocumentTouch)

Fixes #1869
Merge pull request #1867 from bartvde/stability

Mark parts of control and overlay as stable
Merge pull request #1870 from fredj/has-touch

Fix ol.BrowserFeature.HAS_TOUCH detection code
Fix vbarray extern

dimension argument is optional.
See http://msdn.microsoft.com/en-us/library/3kk8f869(v=vs.94).aspx
and http://msdn.microsoft.com/en-us/library/0kbz883e(v=vs.94).aspx
Merge pull request #1872 from fredj/vbarray

Fix vbarray extern