Add recurring tasks generator

[GoogleCodeExporter]

Allows users to define recurring tasks. For example, 'wash the car' every 2 
months. Each time a recurring tasks is triggered, it will be added to the 
Today's page as a normal task (can be edited, moved around, locked, etc).

Things to consider:
1. If an identical task is already in the Today/Tomorrow pages, do not insert a 
new one.
2. Allow one time tasks?   (e.g. like recurring but inserted only once)
3. Allow to pause/enable individual recurring tasks
4. Display for each recurring task when the next insertion will happen?
5. Allow to pick an existing task and make a recurring out of it?  (saving the 
user from having to retype it)

Should have extremely simple user interface. Even at the cost of reduced 
functionality.

Original issue reported on code.google.com by dayans...@gmail.com on 12 Feb 2012 at 6:44

[GoogleCodeExporter]

another thing to consider:
When taks is delayed keep the older and show the newer, not erase uncomplete 
task.

Original comment by jfcari...@gmail.com on 19 Jun 2012 at 5:57

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Original comment by dayans...@gmail.com on 31 Aug 2012 at 4:54

• Added labels: Milestone-R26

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Original comment by dayans...@gmail.com on 25 Mar 2013 at 4:20

• Removed labels: Milestone-R26

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Original comment by dayans...@gmail.com on 6 Jul 2013 at 11:13

• Added labels: Milestone-R27

[GoogleCodeExporter]

I've started an implementation in a clone of maniana, 
https://code.google.com/r/emdroidle-maniana

As of this writing I've got repeats by day operational, while the other repeat 
types are mostly templates without an implementation behind them. Personally, 
this is a *very* important feature, without which Maniana is pretty well 
useless to me.

Original comment by emdroidle on 27 Oct 2013 at 3:05