Allow audience to include multiple mentions, including individual user mentions

[billneff79]

e.g.

• audience @user1 @user2 @user3
• audience @here @userNotHere4
  ...

[codecov-io]

Codecov Report

Merging #158 into develop will decrease coverage by 1.29%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           develop     #158     +/-   ##
==========================================
- Coverage    86.44%   85.15%   -1.3%     
==========================================
  Files           58       59      +1     
  Lines         1372     1374      +2     
  Branches       181      181             
==========================================
- Hits          1186     1170     -16     
- Misses         186      204     +18

Impacted Files	Coverage Δ
lib/bot/setAudience.js	37.5% <0%> (ø)	⬆️
lib/helpers/reports/forChannelUpdate.js	33.33% <0%> (-66.67%)	⬇️
lib/helpers/updateChannelReport.js	19.04% <0%> (-57.15%)	⬇️
lib/helpers/doChannelReport.js	94.73% <0%> (-5.27%)	⬇️
lib/helpers/doBlock.js	91.66% <0%> (-1.67%)	⬇️
models/index.js	92.85% <0%> (ø)
lib/helpers/reports/transformers/index.js	100% <0%> (+7.14%)	⬆️

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