xinitrc, setup: Overhaul of X session handling.

xinitrc, setup: Overhaul of X session handling.

Requires 1.4.0 of xtoys.  The xinitrc now waits for and processes commands
when it's finished.  This involves a major restructuring of the code.

Also tweak window manager bindings to match, and provide useful support
scripts.

The inclusion of movemail-hack is sneaky: while we're moving things into
the collection, we might as well add this too.