Add option to show reminder even if the habit is completed

[iSoron]

Feature request from #263:

woj-tek wrote:

So I have a couple of items with configuration that I want to do them 5 days a week (with the idea that this is "5 workdays") and reminder for such days. However this task can be executed optionally also during weekend.

I've noticed that if I mark the habit on weekend as well then I don't receive notification on the weekday (seems that if the requirement for habit is already fulfilled it disables notification?).

I think there should be an option (either global or per habit) whether notifications should happen at designated day always (despite "completeness" of task) or depend on whether task is considered completed in the given period -- that should solve the issue IMHO