[Koha] 3.4.x Branch and 3.4.8 Release Update

Hi All, I've just had time to bring the 3.4.x branch current with master. We will be releasing 3.4.8 next Saturday. There are a huge number of commits made in the last 8 hours, so I'd like to call for some testing on 3.4.x before the release next Saturday just to avoid any obvious bugs. So if you have a chance to, please test and let me know if you discover anything. Kind Regards, Chris