Add "%w" to pretty formats, which rewraps the commit message

Add "%w" to pretty formats, which rewraps the commit message

Some repositories contain commit messages that are insanely long.
And not always is it an option to rewrite the commits with rewrapped
commit messages; just think of cvsimports or some such.

Now here is a remedy.

With "--pretty=format:%w(8,6,70)" you will get the commit messages
reformatted to width 70 where the first line has indent 8 and the
subsequent lines have indent 6.

The following command will output something similar to plain "git log
--color", except that the commit bodies will be rewrapped to fit inside
80 columns:

	git log --pretty=format:'%C(yellow)commit %H%C(reset)
	Author: %an <%ae>
	Date: %ad

	%w(4,4,80)'

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>