Remove Unused Code

**Danger Will Robinson, this change is based atop #474 and shouldn't be merged until after that pull request has been closed.**

* Closes #494

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.