[Conkeror] New feature: Caret mode / isearch integration

[Nelson Elhage]

Last night, I pushed an improvement to conkeror's support for caret
mode (C-q F7): isearch now starts from and updates the caret's
position if you use it in caret mode. This makes it much easier to
position the caret on a specific piece of text in order to copy it.

John Foerch also discovered that you can use the `focus' command
(bound to ; by default) to move the caret to a browser object in caret
mode, as another way to move to caret around more easily from the
keyboard.

In addition, I'm working on adding support for using the mark and the
emacs movement commands (C-n, C-f, et al.) to manipulate the
selection. My work so far is on the nelhage-caret-mode-integration
branch in git if anyone wants to try it out; I'd appreciate reports on
whether I've accidentally broken anything.


On another note, I fixed a minor bug that was preventing
tab-completion of local paths from working; You should now be able to
tab-complete paths in the minibuffer again when appropriate.

- Nelson Elhage