Add a new fs newalias man page. Add -help to the synopsis and options of
the other new man pages. Add additional missing links in the fs man page.
Fix some wording in the CellAlias man page.
Complete the documentation of the afsd flags and update a few things like
-settime and -nosettime. Add man pages for fs setcrypt, fs getcrypt, and
CellAlias. Based on work by Jason Edgecombe and then extensively edited,
so any errors I probably introduced.
