- Add a test on group by for hbase

- Query results are no longer simple lists of vectors but data frames
- new.table builtin renamed to new.tableRef
- Update to new version of QIR

Implemented TruffleRLanguage.toString(RContext context, Object value) and isVisible() to work properly in GraalVM shell and Interop.

return RIntSequence or RDoubleSequence depending on 'right' parameter
being in integer range or not.

coalesce all seq builtins into SeqFunctions
add fast paths for seq and seq.default
refactor and expand seq unit tests

refactor RPromise: change state to bitfield, synchronized evaluation of explicit promises, fast path for eager promises in MissingNode