[Slack] Direct messages require existing channel

[jaraco]

Following on #57, direct messages are now arriving but only if the channel between pmxbot and the user was already opened.

[jaraco]

I found the slacker project implements a method to open a new IM.

[jaraco]

After several rounds, I believe I have a technique that solves this in 1118.0.3.

[jaraco]

Apparently even with the dual-API technique, this issue was not resolved, though I'm not entirely sure the issue was accurately tested either, because after we switched back to the IRC gateway, the issue persists.

[jaraco]

after we switched back to the IRC gateway, the issue persists.

Although I registered this apparent issue here, I can't find the reason why I said that, and there have not been ongoing issues with notifications except when we know the bot has become disconnected from the server.

[jaraco]

We've since been forced to switch to a Slack-based bot, and no one has complained about this issue. Unless someone complains, I'm not going to worry about it.