Removing RequestHelper class.

So begins the trimming down of this library! I plan to strip out forms
and security into reusable modules, and essentially freeze any further
progress on this framework. It's been fun and a great learning
experience. Let's finish this thing - clean up the code, add some docs
and bump to version 1 - the first and last major release. I want this
release to be stable and usable, with only bugfixes following this release.
Removing Timer class.
Replacing Form and Validate with reform library.
Updating reform use statements.
Updating Assets to use the Url class.