Fixed 'make -j4 check' by putting in test dependencies.

Also needed to make job3 test-case use its own printer name.
Only mark job as started on successful g_spawn_async() call.
.travis.yml: deal with old version of automake.
MIME type auto-sensing fixes.

The Printer's default for document-format is to auto-sense.
Simplified updatedriver1 test-case.
Set final content type for printer based on driver.