html5 demo screen orientation is inverted

In the changes made for to address weston configuration after the merge of the various demo repositories the orientation of the landscape configuration was chosen to match the requirements of the cluster demo versus the HTML5 demo, i.e. 180 degree rotation versus no rotation (i.e. inverted to match the screen installation in the AGL demo system).  It is preferable that the HTML5 demo platform image be usable out of the box, so provision needs to be made for the two different landscape orientations.