Stop/pause miner feature request

[wimbledon]

Feature request:

Implement stop/pause command: when invoked the miner pauses mining.

I know I can simply kill the process and restarted in later time. However, it would be really nice to have the pause command in xmr-stak itself. In some cases, i.e. mobile applications, one needs to kill the whole app to stop the miner.

[psychocrypt]

I am working on this because this will be one feature of the gui and than also be available in the cli version.

[wimbledon]

Great! If you can add to cli that would be super helpful!