#3 calendar nav links should store current environment vars

[Anonymous]

The arrows constituting links on the calendar frontend
do not pass on the current $_GET env vars to the
backend. This means that the default $_GET is used ->
which could possibly change the location of the page in
a dynamic environment. Accordingly, the backend should
receive the current $_GET env and append them to the
generated dynamic month link.

The downside of this approach could be to repeat a
procedure directed by $_GET which should only have
happened once...