This makes it possible to test various settings combinations and
examine internal state to confirm correct behavior. Also, the user
doesn't need to start an Etherpad server before running these tests.
Three of the four tests fail if `settings.allowAnyoneToImport` is
false. The fourth ("tries to import Plain Text to a pad that does not
exist") isn't particularly useful when `settings.allowAnyoneToImport`
is false: That test tests an import failure mode, and when
`settings.allowAnyoneToImport` is false the failure could be caused by
that instead of the expected cause.
Just final bits of test coverage for import/export of LibreOffice. It turns out Travis by default installs an old LO that doesn't support PDF import. To remedy that I use the LO PPA and also strict install the PDF import support.
Still to do in a future date is check LO exported contents includes expected strings, for now it just checks output length looks sane.
