Implement uploading of logs

[tjanson]

Replaces #5.

It has become clear that the Logback SocketAppender approach, while cool and elegant, doesn’t work well under the tricky networking conditions during Wifi scan (lots of network dis- and reconnects).

As much as I would like to stay with a pure Logback solution (e.g., by implementing a HTTPAppener), it will probably be easier to implement a regular, manually triggered upload function. Currently looking into Android-Async-HTTP.

[tjanson]

@a473f5d07c30e3504b49ed78c91003791add3e3e