Replace a couple URLs that don't point to anything

I'm unsure regarding the pygst tutorial, so I just added another URL
of the best resource I could find with a quick web search.

beets/ui/__init__.py

@@ -475,7 +475,7 @@ def human_seconds_short(interval):
 # Colorization.
 
 # ANSI terminal colorization code heavily inspired by pygments:
-# http://dev.pocoo.org/hg/pygments-main/file/b2deea5b5030/pygments/console.py
+# https://bitbucket.org/birkenfeld/pygments-main/src/default/pygments/console.py
 # (pygments is by Tim Hatch, Armin Ronacher, et al.)
 COLOR_ESCAPE = "\x1b["
 DARK_COLORS = {

beetsplug/bpd/gstplayer.py

@@ -64,7 +64,8 @@ class GstPlayer(object):
         """
 
         # Set up the Gstreamer player. From the pygst tutorial:
-        # http://pygstdocs.berlios.de/pygst-tutorial/playbin.html
+        # https://pygstdocs.berlios.de/pygst-tutorial/playbin.html (gone)
+        # https://brettviren.github.io/pygst-tutorial-org/pygst-tutorial.html
         ####
         # Updated to GStreamer 1.0 with:
         # https://wiki.ubuntu.com/Novacut/GStreamer1.0

docs/reference/cli.rst

@@ -453,7 +453,7 @@ available via your package manager. On OS X, you can install it via Homebrew
 with ``brew install bash-completion``; Homebrew will give you instructions for
 sourcing the script.
 
-.. _bash-completion: http://bash-completion.alioth.debian.org/
+.. _bash-completion: https://github.com/scop/bash-completion
 .. _bash: https://www.gnu.org/software/bash/
 
 The completion script suggests names of subcommands and (after typing