Making sure that the start or end date comes from the url.

This is to make sure that a cookie is not overriding the value
of one of those date.

Maybe we should start discussing what other var ought to be
protected that way. I did only those, because I was reasonably
confident that it was the purpose.
Merge pull request #2 from mikeSimonson/master

BugFix: Making sure that the start or end date comes from the url.