first xspec v12.4 patches

A couple of minor patches are now up

12.4.0a

This fixes some cases where invalid input leads to segmentation faults: The model command crashes for certain forms of invalid model syntax. The tclout command crashes for some of its options when the invalid spectrum number 0 is specified while there are data sets loaded. Our thanks to Jeremy Sanders for pointing this out. Report added on Dec 10, 2007. This patch modifies headas/Xspec/src/XSUser/Handler/HandlerUtils.cxx, XSUtil/Parse/Expression.cxx, and XSPlot/Plot/Plot.cxx

12.4.0b

For the model command, entering the abbreviated name bkn should select the bknpower component and not the bkn2pow component. Our thanks to Davide Donato for pointing this out. Report added on Dec 18, 2007. This patch modifies headas/Xspec/src/manager/model.dat