This update for tryton, trytond, trytond_purchase fixes the following issues:

Changes in tryton:
- Version 6.0.56 - Bugfix Release

- Version 6.0.54 - Bugfix Release

- Version 6.0.53 - Bugfix Release

- Version 6.0.50 - Bugfix Release

- Version 6.0.48 - Bugfix Release

- Version 6.0.46 - Bugfix Release

- Version 6.0.43 - Bugfix Release

- Version 6.0.41 - Bugfix Release

- Version 6.0.40 - Bugfix Release

Changes in trytond:
- Version 6.0.70 - Bugfix Release

- Version 6.0.68 - Bugfix Release

- Version 6.0.66 - Bugfix Release

- Version 6.0.65 - Bugfix Release

- Version 6.0.64 - Bugfix Release

- Version 6.0.63 - Bugfix Release

- Version 6.0.62 - Bugfix Release

- Version 6.0.60 - Bugfix Release

- Version 6.0.58 - Bugfix Release

- Version 6.0.57 - Bugfix Release

- Version 6.0.55 - Bugfix Release

- Version 6.0.53 - Bugfix Release

- Version 6.0.52 - Bugfix Release

- Version 6.0.50 - Bugfix Release

- Version 6.0.48 - Bugfix Release

Changes in trytond_purchase:
- Version 6.0.23 - Bugfix Release

- Version 6.0.22 - Bugfix Release

- Version 6.0.20 - Bugfix Release

- Version 6.0.19 - Bugfix Release

- Version 6.0.18 - Bugfix Release

- Version 6.0.17 - Bugfix Release

- Version 6.0.16 - Bugfix Release