[luatex] lua scripts

[Bob Tennent]

> It would be better to allow people to specify an alternative engine on
  the command line instead of changing the code.

  Is it necessary to disallow users to enter the file name properly?

To get the lua scripts into texlive-2011, I had to rush.  I'll refine
the musixtex.lua script. 

> BTW, there is a manual page for musixflx in TeX Live.  I fear that it
  gets lost if you don't copy it to the CTAN package.

It needs revision. I'll get to it ASAP.

Thanks for the suggestions.

Bob T.