remove cinnamon target
Merge pull request #832 from smibarber/remove-cinnamon

remove cinnamon target with much chagrin
Fix enter-chroot on old chroots. Fixes #837
croutonxinitrc-wrapper: Make sure children do not ignore signals

Creating a child resets signal handlers, but leaves ignored signals
unchanged (see "man 2 sigaction" for details): replace "" with a
no-op handler "true".

Test:
 - Logout in LXDE works (fixes #851)
 - Ctrl-C in crosh, or sending SIGTERM to xinit both work (exit
   commands are run).
Merge pull request #859 from drinkcat/xinitrc-fixtrap

croutonxinitrc-wrapper: Make sure children do not ignore signals
mount chroot read-only into ~/Downloads/Crouton/*

This patch bind-mounts $CHROOT read-only into ~/Downloads/Crouton/$NAME
if we're logged in as a user so that we can access chroot files from
Chromium OS' Files application (e.g. when uploading files to the Web).

In addition, mounting read-only protects us from the danger of Chromium
OS deleting files randomly from ~/Downloads whenever disk space is low:

  https://support.google.com/chromebook/answer/1061547?hl=en

In fact, even the root user cannot delete files from or modify files
within a read-only mount without first remounting it as read-write!

I don't think Chromium OS is that aggressive in freeing up disk space.