Make git try work on Windows.

Make git try work on Windows.

This mirrors the git-cl changes by first moving git-try
to git_try.py (which git cl already had), then copying
git-cl to git-try and updating all references to git-cl
and git_cl.py to the corresponding git try references.

The main issue is that in the MINGW/Msysgit case we want
to use the Python in depot_tools since that is 100%
compatible with the Command Prompt.  Hence we need
to call it directly and then pass it the name of the
git_try.py script.

Note that 'git-try' will not (ever) work on Windows,
and users should only ever run 'git try'.  Hence the
need to modify the output of the command to avoid
further confusion.
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=89031

[cmp, 2011-06-06 20:32:23]

This is not tested yet, don't commit!

[nsylvain, 2011-06-06 21:17:16]

LG

[M-A Ruel, 2011-06-06 21:35:47]

lgtm

http://codereview.chromium.org/7114002/diff/1/git-try
File git-try (right):

http://codereview.chromium.org/7114002/diff/1/git-try#newcode5
git-try:5: 
The fact that rietveld decided that it's a replace is confusing.

http://codereview.chromium.org/7114002/diff/1/git_try.py
File git_try.py (right):

http://codereview.chromium.org/7114002/diff/1/git_try.py#newcode1
git_try.py:1: #!/usr/bin/python
While at it, update shebang to:
#!/usr/bin/env python