Allow hierarchical section names

Allow hierarchical section names

A .git/config like follows becomes valid with this patch:

	[remote.junio]
		url = git://git.kernel.org/pub/scm/git/git.git
		pull = master:junio todo:todo +pu:pu

	[remote.ibook]
		url = ibook:git/
		pull = master:ibook
		push = master:quetzal

(This patch only does the ini file thing, git-fetch and friends still
ignore these values).

Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Junio C Hamano <junkio@cox.net>