Formatting the fixture text.

Minor changes.  Experimenting with different ways to format the fixture text in the list on the main screen.
Storing Fixtures in Configurations.

- Created Configuration and Group classes.
- Now store Fixtures in instances of those classes.
- Now reading the data on the main screen (the "current
  configuration" screen) from [LMUConfiguration current].

:-)  Woo!

Wrote code to read the Configuration from disk, but
put a 'return' at the top of that method, so it doesn't
run.  Yet.

Also attempting to tell Git to ignore a bunch of user-
workspace-specific files which aren't part of the project --
anything with "xcuserdata" ("Xcode User Data") in the
pathname.  I'm not sure it worked, although it *seems* to
have worked.  I'll find out on my next run of the app.
Ahem.  :-)

...so I may have to revert this checkin.  IF YOU CHECK
THIS OUT AND THE PROJECT BREAKS, don't worry about it;
just get the previous commit.