emacs: new windmove keybindings

C-c j for left
C-c k for down
C-c l for up
C-c ; for right

need to stop moving my hands to the arrow keys as much.

means that comint-mode's keybindings don't need changed, as they no
longer clash.
emacs: change magit keybindings

Remove "C-c l" for log and "C-c b" for branch manager. They open the
buffer in the wrong window, unlike status which I've configured to use
the current window. Instead go to the status window, then to log or
branch manager if necessary (but usually I can do what I want from the
status buffer).

This means magit-blame-mode can be moved to "C-c b" instead of "C-c B",
and "C-c l" is now available.