Horn doesn't accept web links #81
Description
Using Slack-formatted web links doesn't work in Horn. Examples:
curl -X POST -d '{
"text": "Link: <google.com>!"
}' https://integram.org/webhook/...
curl -X POST -d '{
"text": "Link: <google.com|this is a link>!"
}' https://integram.org/webhook/...
In both cases, all text between < and > is removed.
