Tabbedinterface: mobile tab panel links can now change tab panels
Tabbedinterface: .tabs-style-6 nesting and resize fixed

Bugs were caused by trying to size and position tab panels that
were hidden or contained in a hidden parent element. Fixes are:

* Nested, sliding, tabbed interfaces now work correctly
* On resize, sliding tabbed interfaces are properly sized/positioned
Fixed #2667 by replacing the PNG fallbacks to the alt for splash spages
Merge pull request #2668 from LaurentGoderre/fix-2667

Fixed #2667 by replacing the PNG fallbacks to the alt for splash spages
Merge pull request #2666 from patheard/tab-nested

Tabbedinterface: .tabs-style-6 nesting and resize fixed
Merge pull request #2660 from patheard/tab-content-links

Tabbedinterface: mobile tab panel links can now change tab panels
Resolved merge conflicts.
Ignore node_modules

Makes it easier while switching between the v3.0 & v3.1 builds now that v4.0 is using Node and Grunt