[fix #647] Update Saxon dependency from 9.5.1-5 to 9.6.0-10

[mkraetke]

Update Saxon with respect of the latest Saxon API changes.

[tofi86]

Shall we at least update Saxon 9.6 to the latest maintenance release 9.6.0-10?

@mkraetke did you ever test with a newer version?

[mkraetke]

We experienced some issues with versions later than 9.6.0.7, so we consider this version as stable.

[tofi86]

@rdeltour gave his okay about updating the saxon dependency:

On 25.08.17 at 20:10 Romain wrote:

Tobias: about the Saxon dependency issue, I was just worried that a
maintenance release would break integrations for systems that still use
the older Saxon version. That said, Saxon 9.5 is pretty old now, so I
guess we can be blunt and update to 9.6.

• Old version 9.5.1-5 was released in march 2014.
• Proposed version 9.6.0-7 was released in august 2015.
• Latest version of 9.6 branch (9.6.0-10) was released in December 2016.

Despite @mkraetke writing that they experienced issues with newer versions than 9.6.0-7 I'd like to update the saxon dependency at least to the latest version of 9.6 branch.
All unit tests for this are giving good results.

[tofi86]

Thanks for your contribution, @mkraetke 👏 🎉

[mkraetke]

Glad to help, thank you for your awesome work guys!