added methods for adding aggregates and moved count method to functions.aggregates
Null is a constan

This makes compiling slightly easier but may be a bad idea
as at least one sql textbook claims it is not.
Moved definition of count to functions/aggregates.py
Support for functions in the FROM clause along with the flatten() function for unwinding nested data.
Use the containing field as a prefix
Properly flatten a repeated record
Views can now reference other views
Version bump