Parameterises Speech Rule Engine tomathspeak verbose(default) rules.

Currently, these configuration calls are inside the functions for getting the speech text.  In the case where MathJax-node is being used as a server (like Mathoid), would it make sense to do the configuration once when the environment is set up rather than for each page or each math string the server processes?  I'm not sure how expensive the call is, and whether it matters.  If, for example, it loads rule definition files, it might be best to do it once rather than each time.