update dot_sequences() to use numpy.core.umath_tests.matrix_multiply()
update dot_sequences() to use numpy.core.umath_tests.matrix_multiply()

- more than ten times faster, if available!

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