New condition for convergence on solution and residual

This branch makes it possible to enforce convergence on residual and convergence on solution at the same time. Currently the condition for convergence requires either convergence on residual, or convergence on solution. Now, with this stronger condition of convergence, usually extra iterations are required to fulfil also the convergence on solution, if enabled.

Convergence history with tolerance for solution:

Step(1:0) t=0.2 dt=0.2
	Iteration(0)   0.00845699   CPU:3.297e-06/4.1768e-05+0/4.0416e-05+0/7.0633e-05
		SolErr 0.0875187
	Iteration(1)  0.000641795 J CPU:3.447e-06/5.2388e-05+6.11e-07/4.3873e-05+8.566e-06/9.3806e-05
		SolErr 0.00493688
	Iteration(2)  3.84739e-05   CPU:4.909e-06/6.3199e-05+9.7193e-05/0.000141066+2.4596e-05/0.000118402
		SolErr 0.000314826
	Iteration(3)  1.37651e-07   CPU:2.746e-06/7.6854e-05+7.284e-06/0.00014835+4.408e-06/0.00012281
		SolErr 1.13042e-06
	Iteration(4)   2.9722e-11   CPU:2.625e-06/8.6623e-05+2.364e-06/0.000150714+4.128e-06/0.000126938
		SolErr 2.44137e-10
	Iteration(5)  2.45327e-17   CPU:3.106e-06/9.7544e-05+4.218e-06/0.000154932+5.6e-06/0.000132538

Convergence history without tolerance for solution:

Step(1:0) t=0.2 dt=0.2
	Iteration(0)   0.00845699   CPU:3.867e-06/3.3974e-05+0/0+0/0
		SolErr 0
	Iteration(1)  0.000641795 J CPU:5.58e-06/4.7269e-05+1.694e-06/1.1031e-05+8.586e-06/0.000109716
		SolErr 0
	Iteration(2)  3.84739e-05   CPU:4.428e-06/6.3209e-05+0.000100178/0.000111209+2.0138e-05/0.000129854
		SolErr 0
	Iteration(3)  1.37651e-07   CPU:3.657e-06/7.7596e-05+5.981e-06/0.00011719+6.242e-06/0.000136096