Fix query params inclusion in Query::toAST

[H-Plus-Time]

(Please excuse the PR re-lodge)

As far as I can tell, the Options type is incapable of using params, so I've elected not to pass opt to astOptions (or astTableRef for that matter)

At the moment, getParams is exclusive - so you either get table.params, OR {...t1.params, t2.params} OR query.params. Merging a table or constituent tables' params with those embedded in a query makes sense, though it's uncertain which should have higher precedence - I'm open to implementing this (it's a tiny change anyway), let me know which order you'd prefer.

Closes #222