[Bug-gnubg] Few recent issues (20090922 code)

[Massimiliano Maini]

- toolbar buttons for previous marked and previous cmarked are missing:
there are missing lines in gtktoolbar.c:
  - in the declaration of toolbarwidget
  - in ToolbarUpdate
  - in ToolbarNew

- When a match is anlyzed an you go to the 1st game (or any other)
using the drop down list, the buttons are grayed out. They return available
as soon as you click on any move in a the game record.

- Regarding Jon's changes to analysis settings:  remove my gnubgautorc,
by default the anlaysis is at "expert". Now I change it to WorldClass and
then back to expert, I get this warning:

You must set a count of extra moves and a search tolerance (see `help
set analysis movefilter').

MaX.