Some desktop environments are now checking for free space before
copying files to a destination.
To support this, the FUSE filesystem needs to convert the statvfs()
system call to the relevent PDUs from [MS-RDPEFS]
Constants from MS documents (MS-RDPBCGR etc) moved out of
common/xrdp_constants.h into includes named after the documents.
Similar includes moved from sesman/chansrv to the common area.
matt335672