add Xsession script to launch Unity indicators
use XDG autostart instead of Xsession
unconditionally run croutonversion to get RELEASE
moar unity
Merge branch 'unity-trusty' of https://github.com/smibarber/crouton
Ubantoo 14.04 Trusty Trilobite in, 12.10 Quantal Quagga out.
Temporary workaround for #777 while we investigate googlesource.com
installer/functions: verifykernelsig, verify kernels signature.

Use dev_debug_vboot to figure out if dev_boot_signed_only should
be re-enabled.
test/tests/19-verifykernel: Test if kernel signature check is working.

The test should succeed on all autotest platforms, as they run
official images.
installer/main.sh: Check kernel verification before setting dev_boot_signed_only=1.

Since the test can take up to ~15 seconds to run, we run it in background,
and only update the flag after the bootstrap script has run, but before
the we enter the chroot for the first time.

We also move USB/legacy boot warnings to the end of the script.