Cleaner assemblies

Revision 46631 contains a number of algorithmic improvements. In particular there are now less ‘false’ bubbles in assemblies.  These arise particularly in assemblies at high (> 60x) coverage, as one might have e.g. for a bacterium.  These bubbles have substantial support on both branches but examination of the quality score distributions of the read bases associated with both allows DISCOVAR to kill off one branch.