Nuke xpi-* ports

Legacy extensions aren't supported by Firefox anymore. Very few were
maintained up until last year when AMO stopped hosting files.

- Drop @dirrm* from and add empty directories to pkg-plists

Approved by:	portmgr blanket

- Stage support

Add NO_STAGE all over the place in preparation for the staging support (cat:
www)

- Update to 0.6.20

PR:             167580
Submitted by:   Muhammad Moinur Rahman <5u623l20@gmail.com>
Approved by:    maintainer

Remove more tags from pkg-descr files fo the form:

- Name
em@i.l

or variations thereof. While I'm here also fix some whitespace and other
formatting errors, including moving WWW: to the last line in the file.

- Get Rid MD5 support

- Update to 0.6.17

PR:             129306
Submitted by:   "Alexander V. Ribchansky" <triosoft@triosoft.com.ua>
(maintainer)

- Update to 0.6.15

PR:             ports/107857
Submitted by:   Alexander V. Ribchansky <triosoft@triosoft.com.ua> (maintainer)

- Update to 0.6.14

Add port www/xpi-imglikeopera:

ImgLikeOpera allows load only the images that you want in Firefox browser.
This extension is very useful for non broadband users.

Features:

 * placeholders for blocked images (hi, LJ treads!);
 * (re)load image from context menu or Ctrl+rightMouseClick;
 * forced expiration time (5 minutes - 3 months);
 * one of four policies for each tab:
   o don't load images;
   o load cached images only;
   o load images for the originating Web site only;
   o load all images.
 * filters.

WWW: http://imglikeopera.mozdev.org

PR:             ports/97789
Submitted by:   Alexander V. Ribchansky <triosoft@triosoft.com.ua>