Replace hardcoded API call with parameterized call
Replace hardcoded API call with parameterized call

Previous API call had a preset route and stop the server could retrieve
information for. This commit replaces that preset call with a generic
one that parses the URL string for user-supplied stop and route
arguments.

An example call could be:
"/?route=MTA NYCT_B63&stop=308209"

geoffreyyip/mta-dashboard,geoffreyyip/mta-dashboard