Improves the namin scheme

o Improves the naming of the functions.
o Adds a wrapper for the search on tematres
o Examples:

	bef.search.tematres("ar")
	bef.search.tematres("not available")
	bef.search.tematres.keywords("treefall gap")
	bef.search.tematres.broader_keywords("treefall gap")
	bef.search.tematres.narrower_keywords("Tropical forest")
	bef.search.tematres("treefall gap", "broader")
	bef.search.tematres("Tropical forest", "narrower")