Add global error handling

[antmoth]

Uncaught/unhandled exceptions should: (1) show the user a reasonable error page (2) notify configured tech support/admins

For the simplest possible implementation of (2), we may want to simply direct error reports to a mysql table that can be accessed through the django admin interface, and think about something better later on.

[antmoth]

[antmoth]

Would it make sense/be worthwhile to make the error reports nonmodifiable through the admin interface? I suppose one could delete them as they are dealt with, which would be kind of reasonable actually. This is not probably a high-regulation environment that requires scrupulous and complete logs to be preserved unto eternity.

[antmoth]

tentative error page ^