fix ConcentratedPointLoadTerm.check_shapes() for functions, update docstring
fix ConcentratedPointLoadTerm.check_shapes() for functions, update docstring

RexFuzzle/sfepy,RexFuzzle/sfepy,rc/sfepy,sfepy/sfepy,vlukes/sfepy,BubuLK/sfepy,vlukes/sfepy,lokik/sfepy,lokik/sfepy,vlukes/sfepy,sfepy/sfepy,lokik/sfepy,RexFuzzle/sfepy,RexFuzzle/sfepy,lokik/sfepy,BubuLK/sfepy,rc/sfepy,rc/sfepy,BubuLK/sfepy,sfepy/sfepy