API change: from arbitrary function arguments to objects with named properties

[jmrog]

A number of the stardog.js methods accept 5 or more (often optional) arguments, making it necessary to do things like pass undefined for intermediate arguments, remember the argument order while scanning source code, etc. The API would be much nicer if these methods instead accepted POJOs optional properties. Of course, that would be a big breaking change, so it's for v2.