More lines of context sometimes help to better understand a diff.
This patch introduces a text field above the box displaying the
blobdiffs. You can type in the number of lines of context that
you wish to view. The number of lines of context is saved to
~/.gitk.
Signed-off-by: Steffen Prohaska <prohaska@zib.de> Signed-off-by: Paul Mackerras <paulus@samba.org>