Strip trailing white space. Add browser cache defeat support method
in ApplicationController for use by other controllers in before_filters.
Attempt to defeat browser caching for the sign-in page to reduce the
chance of cache-related JavaScript detection failures. When signing
in with a user name and password, JavaScript detection wouldn't work
at all either; fixed.
Attempt to bypass browser caching on certain actions that are either
highly dynamic or have widely differing behaviour if JavaScript support
is present, within TimesheetsController.

Fix GitHub issue #36 and issue #37.