Fix uniqueTheme example in layertree doc
Merge pull request #832 from camptocamp/uniqueTheme-1.4

Fix uniqueTheme example in layertree doc
Merge commit 'ba43abc2196f5f1edd2705b34e6d9567c982c376'

Conflicts:
	core/src/script/CGXP/plugins/LayerTree.js