fix flake
flake clang.py
forgot to add sql files for clang_tests
code for groupby grappalang
add "complex aggregates" like SUM(a+b) to grammar
move SimpleGroupBy to stock RA rules
use SimpleGroupBy in clang/grappalang
flake8, especially clang
fix complex aggregate datalog test
add test to clang for "complex aggregate"
fix literals in head expression
templatize the hashing operations

for at least things with _+_ and _+1