New HEAsoft release: PyXspec non-backwards compatibility

The next HEAsoft release should occur before the end of the week. This is the first of a few notes on some of the more important changes.

This is the release of v1.0 of PyXspec. Our thanks to everyone who has provided feedback on the pre-v1 releases, the comments have been most helpful. Based on this feedback and some further thought by ourselves, we have made a couple of changes which are not backwards compatible. We hope this will not be too inconvenient and believe that the new syntax is clearer. These changes are:

(1) When using multiple data groups, the Model objects assigned to the higher-numbered groups now all have their parameters indexed from 1 to nPar. For example, with a 3 parameter model applied to 2 data groups, you would now access the first parameter in the 2nd model object with "mod2(1)" rather than "mod2(4)".

(2) The Model.setPars() function (introduced with patch 12.7.0f) used the p# keyword argument syntax to set non-consecutive parameters. This has been replaced by the use of Python dictionaries. For example, m.setPars(p2=.3, p4=1.1) should now be m.setPars({2:.3, 4:1.1}).