* Testsuite: Run UIs in Qemu and check running processes (and other changes)
* When `pmbootstrap qemu` gets killed, it now takes down the Qemu process with it
* `test/check_checksums.py` got a new optional `--build` parameter, which makes
it build all changed packages instead of just checking the checksums
* We run this before running the testsuite now, so all changed packages get
built before running tests (otherwise tests would hang without any output
while a changed package is building)
* New testcase, that zaps all chroots, installs a specific UI (xfce4 and
plasma-mobile currently, easy to extend), runs it via Qemu and checks the
running processes via SSH.
* Version checking testcase: rewritten to include Alpine's testsuite file in
our source tree, so we don't need to clone their git repo anymore. Now it
is enabled for Travis.
* All this gives us a nice 10% code coverage boost
* Increased the `hello-world` pkgrel to verify that the Travis job is working.
* Various fixes
* Build device-packages for the device arch and don't raise an
exception, but print a note if --ignore-depends is not specified
and therefore the kernel gets installed, too.
* Don't use --force when building in Travis (because abuild doesn't
check the checksums then. Bug report on the way.)
* Don't run the building process in the background, but wait for its
completion
* Exit with 1 when showing usage in check_checksums.py
