Added f to todo.
Added intervals to dates.
Tweaked the sloppy todo format a bit making it more restrictive but less likely to mistake non-todos as todos.
Version bumped from 0.1.5 to 0.1.6
Merge branch 'release-0.1.6'
Fixed feature issue that would nuke todos by calculating wrong highest ai value.
Version bumped from 0.1.6 to 0.1.7
Merge branch 'release-0.1.7'