Call execQuery() on non-SELECT queries

For queries which aren't SELECT, the transpiled code itself should call execQuery() in the N1qlQuery instance. Right now, we treat it as query declaration and we don't kick-off the query unless it is iterated over or execQuery() is called on it explicitly.

For example, we're doing this right now -

var q = INSERT INTO x VALUES(k, v);

q.execQuery();

The transpiled code should convert the query as -

var q = (new N1qlQuery('INSERT INTO x VALUES (k, v);')).execQuery();