Documentation/ToolsForGit.txt: Tools for developing Git

Documentation/ToolsForGit.txt: Tools for developing Git

This document gathers tips, scripts and configuration file to help
people working on Git’s codebase use their favorite tools while
following Git’s coding style.

Move the part about Emacs configuration from CodingGuidelines to
ToolsForGit.txt because it's the purpose of the new file centralize the
information about tools.

But, add a mention to Documentation/ToolsForGit.txt in CodingGuidelines
because there is also information about the coding style in it.

Helped-by: Matthieu Moy <Matthieu.Moy@univ-lyon1.fr>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: COGONI Guillaume <cogoni.guillaume@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>