Better parsing errors

[hadley]

> DBI::dbGetQuery(con, "SELECT count(*), date FROM SELECT CAST(time AS date), count(*) GROUP by date;")
Error:
! {"exception_type":"Parser","exception_message":"syntax error at or near \"SELECT\"","position":"27","error_subtype":"SYNTAX_ERROR"}

Would be nicer as:

Error in dbGetQuery():
* Failed to parse SQL
* syntax error at or near \"SELECT\"

Or similar