better config options

It should not be necessary to modify the lib to set config options. Explore this a bit more, and make sure any options we need can be added to instantiation. Maybe a good higher default for message-size is a good idea, too.

See #38

Start by reviewing issue #38 and the configuration code under lib to identify which options currently require library edits. Define the options that should be accepted during instantiation, including the desired message-size default; the work is done when those settings can be supplied without modifying lib.

Written by the indexing model from the issue text.