Option for user to stop streaks from being broken on days when there are no cards due

[shoaib281]

Description

From issue #129, one feature request has been that if 0 cards were due on a particular day, the streak should continue, I've made an option for this in the settings so users can have this feature enabled if they do so wish (it is disabled by default).

Checklist:

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• I've read and understood the contribution guidelines
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  • Latest standard Anki 2.1 binary build
  • Latest alternative Anki 2.1 binary build
• I've tested my changes on at least one of the following platforms:
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[glutanimate]

Hey shabbs,

My apologies for taking ages to get to this. Thanks for the contribution! Makes perfect sense to have an option like that in the add-on.

Will see if I can resolve the merge conflicts and give the changes a try, and will then get back to you.

[techvio-dev]

Is there any progress on that @glutanimate ? this option is a must in this add-on.