Better issue-creation interface

[infotroph]

Issuebot currently uses https://github.com/mbland/hubot-slack-github-issues to open an issue when someone reacts to a Slack message with :book:, because it was the existing script that came closest to doing what I wanted. The result, using all default settings, looks like this:

... which looks like this in GitHub:

... which is ugly, doesn't give an informative title, and doesn't preserve the actual contents of the discussion.

A better implementation should:

• Capture text of the message instead of just linking to it, and ideally capture the whole thread instead of just one message (should this be optional or by default?)
• Allow setting an issue title. This probably requires switching away from a reaction trigger to a text trigger.
• Theoretically could add other bells and whistles (Assignments, milestones, labels...), but probably OK to make people open a browser tab for that.

Possible text interface:

issuebot make issue [in <repo>] [from [last message | this thread]] [with title <title>]