Add sugar for no-argument functions
Test of sugared zero-argument functions
Add const keyword to myrial
Fix some broken tests
Test of myrial constant
Merge pull request #204 from uwescience/andrew_noop_sugar

Create sugar for zero-argument functions
wip groupby grappa
address comment on fluffy code
Check for schema matching for binary bag/set opertions
Test binary bag/set operations
myrial_test: add a few more helper functions

Before, we could only execute queries. Now we can also get plans of
various types directly.
ensure SchemaMismatchException on logical plan
TDD tests for schema issues in while loops
remove boolean expression visitor
myrialang: re-enable distinct on project

We disabled this a long time ago when we were using Datalog as the
only demo language. Now we have MyriaL and SQL where it is easy
and natural to distinguish between set and bag semantics. Thus, add
set semantics back to the Project operator, which fixes Datalog.
tests for proper groupby creation in datalog
remove irrelecant comment
fix bug in compiler visitor
add agg+agg to syntax
make datalog.toRA work for any aggregates or expressions in head

based on discussion with dhalperi
on complex expressions in #209