#263 Setting sort of AI in XML

[ZjelcoP]

For AI-scenariobuilding it is desirable to determine by XML whatAI is played.
Sometimes Hard-AI is good, Sometimes doNothing-AI or Medium-AI.
Sometimes a mix. Mapmaker knows best about this by testing and design.
Also possibillity to set editable to false to prevent player from #$^!-ing up the settings.