add two failing sql reduction tests
path works on expressions with more than one input

Used to assume expr had join.  Now it uses inputs.  So it works on join
keywords works on class constructors

but not on carray

Conflicts:
	blaze/bcolz.py
correct imports for keywords bcolz
expr: add path-split function
expr: Split function to chunk expressions
expr: split distinct operations, fix split
summary string printing
expr: split on summaries
wip: split expr on by, expose error on summary
path exits cleanly
move binary operators up to tableexpr
expr: ensure that summary.child is not a reduction
expr: summary child must be tableexpr
ensure that path-split on summary of one reduction returns summary
Add testing for pytables light dd
Implement pytables ligth
Implement np.ndarray <- tables.Table for time64col
Flesh out testing
Return if there are no time64 fields