Remove Unused Code

* Closes #494

Remove references to bits and pieces of unused code which have been left over from the new MP profile pages and redesign work.

Includes changes to how errors are handled in member pages (now using exceptions and catching rather than setting `$error` variables, applies more consistently across various places members are trying to be identified). Also introduces [Whoops](http://filp.github.io/whoops/) for showing pretty error messages during development.