Cosmetic
Fixes to match GATK more closely
Revert "Optimization: use integer Phred scores during recalibration"

This reverts commit 551b4096ef7eb1e4a0660f4e6803db60e7b21a06.

Conflicts:
	adam-core/src/main/scala/edu/berkeley/cs/amplab/adam/rdd/recalibration/Recalibrator.scala
Fix global delta
Use doubles throughout for improved accuracy
Reproduce GATK's error estimates
Round to nearest Phred score instead of towards zero
GATK uses smoothing=0 for output to CSV