DrServer auto start/stop

[maru]

Based on ticket #763. DrServer which starts/pauses automatically based on information if PC is idle, or if CPU usage is at specified level. Useful for example if users are working on some non resource heavy tasks on PCs which are at the same time used for DR. Would work only with "search LAN during rendering".

[Yehat]

Will it connect with all avaliable nodes, or only with nodes in list? Its impotant when several people are working with farm together and divide nodes among themselves.

[Ondra]

not planned, it would be quite arbitrary decision when to render. It should be solved with process priority