Plasma/libplasma2/outofprocessdataengines

Discussion

Even if they try to be s async as possible, right now dataengines could become too heavy and slow down the main GUI event loop.

Proposed Solution

Dataengines could run in a different process (and pass the actual data trough sockets) making the UI actually faster. However especially on devices a process more would bring more context switches and overall memory consumption (MeeGo certification policy even forbids applications to run any kind of daemon) So should be probably decided at compile time.