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 #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
Remove tests for spherical geometry on poorly defined points
Fix return types
Fix fixing of OGC stupidity
Parse coordinates in GML in a single pass
Add ol.Sphere#interpolate
Add EPSG:4326 tests
Merge pull request #1873 from twpayne/sphere-interpolate

Add ol.Sphere#interpolate
Do not update RTree while dragging vertices
Merge pull request #1874 from twpayne/wfs-fixes

Miscellaneous GML and WFS fixes
Merge pull request #1875 from ahocevar/modify-performance

Do not update RTree while dragging vertices
Move function declaration out of the constructor
Store touch coordinates as ol.Pixel instead of goog.math.Coordinate
Cache the result of goog.object.getCount
Remove trailing newlines
Remove unused ol.pointer.PointerEvent#originalEvent
Merge pull request #1881 from fredj/pointerevents-cleanups

Miscellaneous pointer events cleanups