Merge remote-tracking branch 'upstream/master'

Conflicts:
	layers.xml
Merge remote-tracking branch 'upstream/master'

Conflicts:
	layers.xml
Tweaking URL in checked/unchecked images.
Made entire layer item clickable.
Fixes to layers, clickable layer list exception

Tweaks to layers.xml, minor fixes to layer list.
Merge pull request #17 from DVAlhadeff/master

Reconciliation and minor fixes to layers.xml/layer list