Added some more SubqueryFlattener tests
Switch SubqueryFlattenerTest to new parameters

so that intellij can run a single resource
ADded some yaml test for count of count
Don't flatten aggregates with more than one from
Prevent Count(*) on the outside

this can be more lenient, if there's no aggregates on the inside,
then it can be flattened
prevent flattening when count refers to expression

you can't do COUNT(c1+3)
Updated readme
Slightly less restrictive for COUNT(*) flattening
Encapsulated method
Added a couple comments
Handle delete/update & null resultColumns
handle null resultColumns correctly

if there's no resultColumns, they can't prevent nesting
Extracted method
Added some more tests
Added test for non-AggregateNode aggregates
Support for method call aggregates
Added missing line to README
Don't fall over if there's no subquery
merge ScottDugas: Count of a count

Merge pull request #1563 from ScottDugas/sql-layer/count-count
https://github.com/FoundationDB/sql-layer/pull/1563