Add option to row key order salted rows, modify scan plan to honor the new option
Merge branch 'master' into saltbug

Conflicts:
	src/main/java/com/salesforce/phoenix/execute/ScanPlan.java
	src/main/java/com/salesforce/phoenix/iterate/MergeSortRowKeyResultIterator.java
	src/main/java/com/salesforce/phoenix/util/TupleUtil.java