Hey dood.
Many thanks that you fixed #109 , it helped me view my slack and IRC messages in one buffer.
I just want to point out when using slack-message-custom-notifier, the arguments are not plain text/string as in you can plug it in alert but objects. So in order for me to get the team, room and message; I had to copy the code from the original alert notification and plug in the correct parameters.
I have no problem that the arguments are objects, but rather I had to go look at the source just to figure what they were. So maybe some documentation on the API objects might alleviate this confusion in using the custom notifier.
Either way, good job.