Added BatteryHolder_Keystone_3002

[valerionew]

New pull request based on the current master, to avoid problems with travis CI.

Deprecates #1183, which will be kept open for testing and analyisis purposes upon mantainers' request.
See:
#1183 (comment)
#1384
KiCad/kicad-library-utils#302

A larger pad than the minimum in the datasheet is used for the negative pad, to improve the direct pcb-battery contact.

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• Provide a URL to a datasheet for the footprint(s) you are contributing
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[poeschlr]

Thanks, looks good