Bug 861181: Separate interface from implementation for nsColumnSetFrame. [r=roc][a=akeybl]
Bug 861182: Pull knownFeasibleHeight and knownInfeasibleHeight into ReflowConfig so they can be used outside of nsColumnSetFrame::Reflow(). [r=roc][a=akeybl]
Bug 857324: Make column set reflow continue without balancing rather than restarting if computed height is exceeded. [r=mats][a=akeybl]