centered copyright text
updates to homepage

https://github.com/mozilla/CSOL-site/issues/116#ref-pullrequest-13402271
updated filter menu and icons
Template and styles for single activity
A start at standardising error handling
Using new error handling
Using new error handling
Don't need logging here
Adding `new`s.
Adding another `new`
Merge pull request #252 from andrewhayward/error-handling

Merging error handling, with the caveat that @stenington will fix the tests that this will break.
Merge pull request #250 from coryshaw/master

Template Updates