[BUG #8486] first attempt to leaner qx.core.Environment usage in toolchain (i.e. without using _checksMap)
[BUG #8486] empty _checksMap temporarily
[BUG #8428] Added unit test
[BUG #8504] qx.Mobile List Group Header should be sticky
* Added a sticky mixin to common SCSS
* used that sticky mixin inside qx.Moblie List headers.
[BUG #8504] qx.Mobile List Group Header should be sticky
* Default to position static if sticky is not supported, for keeping sure "top" does not move all elements.
[BUG #8505] qx.Mobile Scroll container should fire momentumStart/momentumEnd event
* Added detection of momentum, and firing "momentumStart"/"momentumEnd".
[BUG #8486] remove unneeded method
[BUG #8486] enable _checksMap again
[BUG #8486] empty _checksMap again