Implement periodic GPS tracking when device is in sleep mode

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It could be realy cool, if this app can perfom as a "tracker with map".

There should be an option to disable GPS when screen goes dim,
and a configurable timeout to do "Fix-then-sleep" for trackloggng.
So, if user want to look at constantly updating position ( backlight is 
running) - OK, GPS and logging is running constanly,
BUT if user is not looking ( backlight is off) - GPS goes off,
and restart only if timeout happens or user wake up the device.

This should give a "Good enough" approximation of recorded track and realy 
noticeable power economy.

Track line should be updated on screen using recorded points when
user wake up the device.

Additional improvments of this algoritm:
1. Skip first(2..3) gps data after restart - this improve accuracy.
2. Wait for best fix after restart - this improve accuracy, i.e.
   if have a 2D fix - wait more 30 sec for 3D fix, or if we have
    5 sat fix - wait 7 sec more for 6 sat.
3. Limit one try by time, i.e. if no fix more 4 min - GPS off and sleep for 
timeout interval.
4. Use gyro sensor. If there was not movmets in "watch window" - skip GPS. I 
dont know about accuracy of g-sensor to allow shake or vibration detection, but 
this is for investiagtion.

Original issue reported on code.google.com by Gari...@gmail.com on 31 Jan 2011 at 2:19

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Original comment by novikov on 31 Jan 2011 at 7:09

• Changed title: Implement periodic GPS tracking when device is in sleep mode
• Changed state: Accepted
• Added labels: Component-Logic, Performance, Type-Enhancement
• Removed labels: Type-Defect

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Original comment by novikov on 16 Jan 2012 at 12:56

• Added labels: Priority-Medium
• Removed labels: Priority-Low