vfs:  Add general_methods to filehandle_method_set
vfs:  Define general_method_set
vfs:  Add filehandle mmap() primitive
Genie:  Call mmap() primitive from _relix_mmap()
Genie:  Implement mmap method for bitmap bits
Genie:  Implement mmap method for memory buffers
Genie:  Implement mmap method, axe TempMem_IOHandle
Genie:  Implement mmap method for /dev/zero

As before, any of the simple devices can be mmapped with the same effect
as /dev/zero.
Merge branch 'mmap-methods' into mmap-primitive
vfs:  Add map_file() function
vfs:  Implement default mmap for regular files
Genie:  Axe RegularFileHandle::Map()

This logic has moved to the mmap() primitive, and this code is no longer
called.
vfs:  Don't call filehandle::Map() from mmap()

All remaining Map() overrides implement mmap methods, so it's redundant.
vfs:  Axe obsolete filehandle::Map()
Merge branch 'mmap-primitive'
Genie:  Use vfs::map_temporary() in tempmem_mmap()