include tolerances in error checking in conv_test()
include tolerances in error checking in conv_test()

- fixes 'or' eps mode with eps_a == 0.0 and zero initial residual

rc/sfepy,sfepy/sfepy,BubuLK/sfepy,BubuLK/sfepy,BubuLK/sfepy,vlukes/sfepy,rc/sfepy,rc/sfepy,sfepy/sfepy,vlukes/sfepy,vlukes/sfepy,sfepy/sfepy