changed so that invalid paramaters are not treated as hard errors, as th...

...ey can be caused by crawlers malformed links etc, and instead inform the user.
https://code.google.com/p/otwarchive/issues/detail?id=3919&thanks=3919&ts=1392660704
https://rpm.newrelic.com/accounts/115892/applications/190034/traced_errors/1005876650?original_error_id=1006005701

https://code.google.com/p/otwarchive/issues/detail?id=3933
Please add ```and return``` after the redirect - a redirect does not end the execution of a method, and it could lead to "double render" errors.