Add Eini and Efin to sp.technique.Sweep()

[oliverrdz]

Change Sweep() to include Eini and Efin plus Ev1 and Ev2 where v means vertex. This way, if Ev1 is negative more negative than Eini, Sweep() should know that it is a negative sweep, etc. The pull request that tried to do this did not include Ev1 and Ev2. also, the t array is not being calculated correctly, it gives the wrong number of elements and values; this class was changed to sp.Technique.Sweep2() while it is fixed.