Add initial plumbing for window functions
Add support for SUM window function
[SQ] Add support for AVG window function
[SQ] Add MIN/MAX window functions
[SQ] Add COUNT window function
[SQ] Add stddev, stddev_pop, variance and variance_pop window functions
[SQ] Add RANK() window function
[SQ] Add row_number() window function
Add framing clause parsing, support framing clause for SUM
Bug fixes for window frames, add window frame clause support to avg
[SQ] add window frame support to remaining aggregate window functions.  Add dense_rank too
Fix problem with sorting the window frame
[SQ] add percent_rank window function
[SQ] Add cumulative distribution [cume_dist()] window function
[SQ] Add support for NTILE window function
[SQ] Add last_value and first_value window functions
Add support for aggregate functions as arguments to window functions.  Fix
[SQ] Bug fixes for window functions
Major rework of how window functions work internally
[SQ] Fix for window functions