allow OOXML strict relationships in writer

Change-Id: I1c09280f68467748faedee19c4a66be3bc7d7aa3
add import test for strict OOXML import in calc

Change-Id: I4dc0fb84cc9e2601e7ae8b82a467787388ac4d99
add experimental export file validation

In calc unit tests we validate the exported OOXML files now with
officeotron.

For this there must be a script called officeotron that takes the file
path.

Currently the generated files are still invalid but I'm going to fix it.

Change-Id: I1809b9457a535dbbe6a72f3778dfb53db168bbda
remove remaining parts of the old crash testing

Change-Id: I2282d2ee8304bdc9dbdf24c5a22c16d0e742deb7