Updated MySQLFacade to take an id argument when collecting call(s) - now
can collect one or all of them. (note: still need to add output for when
no result is found - wrong id), ditched filesystem output of JSON - now
using Calls servlet to display JSON in browser. Mapping SQL results to
Call objects then mapping those to JSON.

Servlet url syntax:
/Calls				will return all calls.
/Calls/myCallId		will return a specific call.

Should a single call still be displayed in a JSON array like when they
all come back? Currently is.