Checks for git user details (issue3182041)

[percival . music . ca]

Reviewers: ,

Message:
Patchset 1 contains the actual improvement to lily-git.tcl.  It works on
my machine, and I'll push it in 24 hours if nobody complains.


Patchset 2 adds indentation from emacs.  The commit message isn't
showing up, so here it is:

This is the only tcl file in our repo.  It doesn't have a long history,
nor is this file at all important to compiling+debugging lilypond.  As
such, I feel justified in tossing it through emacs' indentation.

This does not mean that I think it is appropriate to discuss the
indentation of any other type of file in git.  If anybody complaints
about indenting this file, I will remove this commit without question,
and we will keep on using the previous inconsistently-indented version
until we discuss code indentation as part of GOP.


Description:
Checks for git user details

Checks global .gitconfig for name and email.

If none found, prompts for entry.

Please review this at http://codereview.appspot.com/3182041/

Affected files:
  M scripts/auxiliar/lily-git.tcl