Fix #45; add description to filters
Fix #44; add description to interactions
Document nil return
Add example
Fix #76; move modules into directory
Fix tests
Make module tests consistent
drop is a little more clear here
Clean up imports
Move inputs below initialize

I accidentally left them up there when I changed them from an
attr_reader to a bona fide method
Fix #75; clean up instance variables
Add space after guard clause
Update changelog
Version bump to 0.8.0