Foliadocserve

* Implemented extra protections in case document serialisation fails
* Better log output on such failure
* foliadocserve goes into a lockdown mode, prevent new document from being loaded
* Implemented extra protection in case contact with the background autoupdater thread is lost after a certain time limit (same lockdown mode)

* Added support for git --shared (enabled by default for group) using ``--gitshare`` (11)
* Added option to choose between different git modes using ``--gitmode`` (11)
* monolithic (ALL users share a single repository, NOT recommended because of scalability)
* user (each user/namespace is its own git repository; this is the default)
* nested (each subdirectory is its own git repository, maximum scalability)
* Implemented sane stop behaviour (12)

* Added support for FoLiA v1.5; strip all text redundancy by default (10)

Minor bugfix release: ensure all JSON properties use double quotes (invalid JSON otherwise), fixes proycon/flat110

Minor fix release:
* Increased max allowed upload document size to 1GB instead of 100MB (fixes proycon/flat109)

Update release, to be used with FLAT v0.7.1:
- Important fIxes in session handling (8), now properly support concurrency (proycon/flat106)
- Fixes autounload problem (proycon/flat105)
- Propagate page size to clients
- More verbose logging