I had code in there to put "No commits selected" on the canvas
but it needed some globals.

Check that $GIT_DIR (or .git, if GIT_DIR is not set) is a directory.
This means we can give a more informative error message if the user
runs gitk somewhere that isn't a git repository.

If the user pastes in the selection (with the middle mouse button) and
it already has 40 characters in it, clear it before pasting.

Right-click on a context row now brings up a menu allowing the user to
generate a diff between that row and the selected row.  Left-click on
a graph line shows the parent and children connected by the line in
the details pane.  Left-click on a circle in the graph selects that
commit.  Left-click elsewhere in the graph does nothing.

When displaying a diff, the bottom-right file list box behaves
slightly differently now; instead of eliding all other files' diffs,
it now just scrolls the details pane so that the selected file's diff
starts at the top of the pane.

Since the diffs can be rather large, arrange for an update to be done
every 100ms while reading diffs.

Also removed the CVS revision keywords and bumped the version number
to 1.2.

In particular try hard to give different colors to lines that cross
at a corner in one of the lines.

This involves adding indentation when we read a commit with
git-cat-file and trimming the whitespace from the headline.

With --header, git-rev-list gives us the contents of the commit
in-line, so we don't need to exec a git-cat-file to get it, and we
don't need the readobj command either.
Also fixed a residual problem with handling the commit that
has a parent listed twice.

This allows the user to specify ranges more flexibly; for instance
the user can now do "gitk v2.6.12.." and see all the changes since
2.6.12.

This happens in the linux-2.6 tree.  We draw the graph line
double-thick to show that this happened.

Also fix a bug where we got a bogus "No commit information available"
line at the end on simple repositories like this one.

Added context menu on lines
Added headline display when the mouse hovers over a line
Removed some debug messages

Display a watch cursor when reading the commits initially

Some speedups from not doing update so often

Fix bug in changing font size in entry widgets.
Fix bug with B1 click before anything has been drawn.
Use "units" and "pages" instead of "u" and "p" for tk8.5.

with a label.
Allow SHA1 ids or tags to be entered in the SHA1 ID field.

Add 'f' key for moving to next file

Put (deleted) or (created, mode xxx) in header lines
Fix scrolling to bring lines on screen

Make up/down/pgup/pgdn work again
Return in find string entry does find
Scale circles and lines with font size
Fix scrolling to make entire selected line visible
Use white circle for commits not listed but put in to terminate lines
Fix diff parsing for created and deleted files

Stop . bindings firing on find string entry keypresses
Fix geometry saving/restoring a bit
Show the terminal commits
Highlight comment matches in the comment window

to keep the proportionality of the pane widths as the overall
window is resized.

Added control+/- to increase/decrease font sizes
Rearranged code a little.

Add a find facility to search within the commits
Cope with multiple starting points.

Fix crash benh saw with currentid undefined
Add menu with file/quit and help/about items
Add ^Q for quit

Selecting in the listbox reduces the text view to just the
diff for the file(s) selected
Added -c option for color-by-committer
Added some more key bindings

Add some scrollbars

use a panedwindow for the main list with three panes,
and make them scroll together

Make it cope with commits having parents that aren't listed.