put anonymous analytics for every call

[sinan]

• all remote calls should be measured
• a checkbox should be put in the package settings screen to turn it on and off

it's important to keep the location data and the duration of the calls to improve the service.

[usirin]

@sinan I am thinking about using google analytics here, it's gonna probably be based on how https://github.com/atom/metrics works.

I will try to be as generic as possible to make it extendable for future use.

Is there anything else we want to measure other than remote calls for the first version?