added coalesce_attribute; Attribute now SHOULD have dimension specified on initialization
added coalesce_attribute; Attribute now SHOULD have dimension specified on initialization

coalesce_attribute converts a string or a dictionary to Attribute
instance, if Attribute is passed then no conversion happens

noyeitan/cubes,ubreddy/cubes,pombredanne/cubes,ubreddy/cubes,noyeitan/cubes,cesarmarinhorj/cubes,zejn/cubes,zejn/cubes,jell0720/cubes,pombredanne/cubes,cesarmarinhorj/cubes,she11c0de/cubes,noyeitan/cubes,jell0720/cubes,pombredanne/cubes,zejn/cubes,she11c0de/cubes,cesarmarinhorj/cubes,jell0720/cubes,she11c0de/cubes,ubreddy/cubes