Pull Request for Issue1007: MCPFileWriter crash bug

Something like this?

I apparently also pushed up outstanding changes to REIXSXESScanActionController() - the AB was failing to compute the cached energy axis values because the scanInitialConditions were not available.  Something clearly changes in the sequencing in scanActionController.  I resolved this by moving the scanInitialConditions initialization into it's own method (for clarity) and calling it in buildScanControllerImplementation() right before the AB is instantiated, instead of in initializeImplementation(), which is apparently too late.