Remove unnecessary quotes around git alias

This is shell-like not C-like, you don't have to be in quotes to escape,
and quoting is really only useful "if you want to preserve leading or
trailing whitespace, or if the variable value contains comment
characters (i.e. it contains # or ;)".

http://git-scm.com/docs/git-config#_syntax
Add git {root,}sgrep to transparently grep submodules

`git submodule foreach` actually has a --recursive option, but
[apparently][] it's breadth-first whereas grep we want to be
depth-first, so recurse explicitly.

[apparently]: http://stackoverflow.com/q/14846967/362030

God, the interplay of [git-config quoting][] and shell quoting is
horrendous, though I think I got it to be reasonably minimal.

Many of the git-grep options don't play well with this, for example, the
context options (-A, -B, -C), and --break, don't show the separators
between results from different submodules, and they can't without this
script doing options parsing.

About `less -FRSX` being git's default pager, search for "FRSX" on:
http://git-scm.com/docs/git-config/1.9.5