core: Add +LPE+ feature to proper X_DLNADOC node
core: Add +LPE+ feature to proper X_DLNADOC node

Add capability to enable LPE feature in device xml

Conflicts:
	src/librygel-core/rygel-description-file.vala
	src/librygel-core/rygel-plugin.vala

Tarnyko/rygel,GNOME/rygel,Tarnyko/rygel,GNOME/rygel,GNOME/rygel