* backend.filehandles maximum filehandles used
* backend.mmap_window_size mapping window start size
* backend.as_limit address space limit
This needs to be changed to use the lumieraorg_configuration interface.
Quite some code which was hold back in favor of the config and plugin stuff
implements:
* mmapcache: mru cache for unused memory mappings
* mmap: single mmaped areas
* mmapings: manages mmaps established for one filedescriptor
