gitk: Move hard-coded colors to .gitk

The Preferences dialog gives control of the colors of some elements of
the gitk user interface, but many are hard-coded in the gitk script.
In order to allow these to be customized through the gitk config
file, these other colors are stored in variables which can be set
in the config file, thus providing a way for color schemes to be stored
and shared.

For win32, this makes the default foreground color that of window text
rather than button text.

Signed-off-by: Gauthier Östervall <gauthier@ostervall.se>
[paulus@samba.org: Reworded commit message to be clearer,
 changed filesepfgcolor to black]
Signed-off-by: Paul Mackerras <paulus@samba.org>
gitk: Improve behaviour of drop-down lists

The drop-down lists used for things like the criteria for finding
commits (containing/touching paths/etc.) use a combobox if we are
using the ttk widgets.  By default the combobox exports its value
as the selection when it is changed, which is unnecessary, and sometimes
the combobox wouldn't release the selection, which is annoying.

To fix this, we make these comboboxes not export their selection,
and also clear their selection whenever they are changed.  This makes
them more like a simple selection of alternatives, improving the look
and feel of gitk.

Signed-off-by: Paul Mackerras <paulus@samba.org>
gitk: Display the date of a tag in a human-friendly way

By selecting a tag within gitk you can display information about it.
This information is output by using the command

 'git cat-file tag <tagid>'

This outputs the *raw* information from the tag, amongst which is the
time - in seconds since the epoch. As useful as that value is, I find it
a lot easier to read and process time which it is something like:

 "Mon Dec 31 14:26:11 2012 -0800"

This change will modify the display of tags in gitk like so:

  @@ -1,7 +1,7 @@
   object 5d417842efeafb6e109db7574196901c4e95d273
   type commit
   tag v1.8.1
  -tagger Junio C Hamano <gitster@pobox.com> 1356992771 -0800
  +tagger Junio C Hamano <gitster@pobox.com> Mon Dec 31 14:26:11 2012 -0800

   Git 1.8.1
   -----BEGIN PGP SIGNATURE-----

Signed-off-by: Anand Kumria <wildfire@progsoc.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
gitk: Simplify file filtering

git diff is perfectly able to do this with '-- files', no need for
manual filtering.  This makes gettreediffs consistent with getblobdiffs.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
gitk: Add menu item for reverting commits

Sometimes it's helpful (at least psychologically) to have this feature
easily accessible.  Code borrows heavily from cherrypick.

Signed-off-by: Knut Franke <Knut.Franke@gmx.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>
gitk: Add support for -G'regex' pickaxe variant

git log -G'regex' is a very useful alternative to the classic
pickaxe.  Minimal patch to make it usable from gitk.

[zj: reword message]
[paulus@samba.org: reword droplist item]
Signed-off-by: Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>
Signed-off-by: Paul Mackerras <paulus@samba.org>
gitk: On OSX, bring the gitk window to front

On OSX, Tcl/Tk application windows are created behind all
the applications down the stack of windows.  This is very
annoying, because once a gitk window appears, it's the
downmost window and switching to it is pain.

The patch is: if we are on OSX, use osascript to
bring the current Wish process window to front.

Signed-off-by: Tair Sabirgaliev <tair.sabirgaliev@gmail.com>
Thanks-to: Stefan Haller <lists@haller-berlin.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Merge git://ozlabs.org/~paulus/gitk

* git://ozlabs.org/~paulus/gitk:
  gitk: On OSX, bring the gitk window to front
  gitk: Add support for -G'regex' pickaxe variant
  gitk: Add menu item for reverting commits
  gitk: Simplify file filtering
  gitk: Display the date of a tag in a human-friendly way
  gitk: Improve behaviour of drop-down lists
  gitk: Move hard-coded colors to .gitk
Git 1.8.3-rc2

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Sync with 1.8.3-rc2