tweaked exception messages, added Term.get_kwargs()
tweaked exception messages, added Term.get_kwargs()

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