Time to update the http://www.omnisharp.net/ to reflect recent changes

[troydai]

Update:

1. Slack room
2. Crew
3. ASP.NET RC2

[willl]

@peterblazejewicz Since you seem to be making a lot of changes lately, do you mind making a change so it links to the Slack team (self-invite form) rather than JabbR?

Thanks!