v0.5.1

This release contains a number of fixes, a few more model helper methods, and
additional framework features.

Thanks to the following for their contributions:

• @acdenisSK
• @ConcurrentMarxistGC
• @FelixMcFelix
• @indiv0
• @Lakelezz
• @perryprog
• @zeyla

Added

• [framework] Add way to register middleware functions directly on
  CreateCommand (@acdenisSK) c:d193975
• [model] Add Message::member (@zeyla) c:ce2952a
• [http, model] Add functions to reorder a guild's channels (@zeyla)
  c:ab1f11a
• [voice] Add multiple audio stream playback, volume control, and pausing
  (@FelixMcfelix) c:324a288

Fixed

• [framework] Fix incorrect skipping for some prefixes (@ConcurrentMarxistGC)
  c:76bcf7d
• [framework] Trim content after prefix mentions (@Lakelezz) c:27c83e8
• [voice] Strip RTP header extensions if present (@indiv0) c:e4612ac
• [voice] Fix voice websocket loop termination (@indiv0) c:55fa37a
• [model] Account for guild owners in member hierarchy check (@zeyla)
  c:03a7e3e
• [model] Check message ID count in delete_messages (@zeyla) c:92c91b8
• [model] Correctly set newly created roles' positions on new roles (@zeyla)
  c:5a0b8a6
• [voice] Fix an odd-to-use Into<Option<Box<T>>> bound (@zeyla) c:eee3168
• [framework] Fix case insensitivity for aliases (@Lakelezz) c:d240074
• [docs] Fix broken docs links caused by model module changes (@zeyla)
  c:8578d5f

Misc.

• [general] Reduce number of clones in the library (@zeyla) c:13b0de1
• [example] Add voice receive example (example 10) (@zeyla) c:b9a7e50
• [examples, framework] Add docs for customised help functions (@Lakelezz)
  c:7912f23
• [example] Add another message embed builder example (@perryprog)
  c:aba1ba6