do not run norm_fit test if there is not enough variation in the insert size
Merge pull request #46 from srl147/devel

do not run norm_fit test if there is not enough variation in the insert ...
added checks for zero peaks
more informative log messages
Merge pull request #47 from srl147/devel

added checks for zero peaks
Merge pull request #48 from wtsi-npg/devel

merge changes from devel for release 56.13