Don't need to cov in an arm ARCH
Only try to build chroot etc. when ARCH=arm, else run tests normally
Only need to run envvars.sh when inside chroot
Install needed Python packages when outside chroot
Because Ubuntu isn't Debian

GUEST_DEPENDENCIES is for a Wheezy arm instance; without that we're on
Precise, so no python3-pip for example
Run coveralls under Python 2.7 for convenience

Ubuntu Precise, the current Travis version, doesn't provide
`python3-pip`. As an experiment, and since this is "only" test coverage,
this drops coverage run to ("native") 2.7 rather than faff with getting
a Python 3 pip as "pip" or doing some sort of conditional hackery on the
"pip install" to use "pip-3.2" in some cases.
Source envvars.sh inside run_tests if it exists

Slightly clutching at straws here but it seems like
e9f5ce62431757bd0a98fae39913e3138c2acb5b broke the tox filter; I believe
that's because of environment variables / lack of export / subshell
mechanics that this _should_ fix...
Don't allow failures of cov, since it now passes
File convention was spaces, not tabs, sorry!
Merge branch 'master' into feature/qemu-when-needed

Conflicts:
	.travis.yml
Merge pull request #35 from py3minepi/feature/qemu-when-needed

Don't run cov inside the qemu-chroot-y-thing