Merged from trunk 6971:6981

   Merged from trunk 6971:6981

   +------------------------------------------------------------------------+
   | 6972   | add hashlib support for checksum verification, refactor       |
   | genone | checksum functions to not look like a complete mess           |
   |--------+---------------------------------------------------------------|
   | 6973   | Allow sync for unpriviledges users if they have write access  |
   | genone | to $PORTDIR                                                   |
   |--------+---------------------------------------------------------------|
   | 6974   | syntax error                                                  |
   | genone |                                                               |
   |--------+---------------------------------------------------------------|
   | 6975   | s/!owned/replaced/ in merge output to clarify it              |
   | genone |                                                               |
   |--------+---------------------------------------------------------------|
   | 6976   | sort the world file before writing it and ensure that it's    |
   | genone | terminated by a newline                                       |
   |--------+---------------------------------------------------------------|
   | 6977   | change default diff_command for emacs (bug #147558)           |
   | genone |                                                               |
   |--------+---------------------------------------------------------------|
   | 6978   | dont break when the binhost url doesn't end with a slash (bug |
   | genone | #144440)                                                      |
   |--------+---------------------------------------------------------------|
   | 6979   | highlight world packages in --pretend output (bug #142473)    |
   | genone |                                                               |
   |--------+---------------------------------------------------------------|
   | 6980   | Add a pointer from FETCHCOMMAND to RESUMECOMMAND (bug         |
   | genone | #141550)                                                      |
   |--------+---------------------------------------------------------------|
   | 6981   | get ACCEPT_KEYWORDS from the env in gvisible() to properly    |
   | genone | handle negated values (bug #139600)                           |
   +------------------------------------------------------------------------+

svn path=/main/branches/prefix/; revision=6994