Uodate Slack alert message
Uodate Slack alert message

* Message is now more clear (subject is the bold title and the message is under
  it. No username in the quote).
* Added pretext to hilight everyone on channel (when default Slack hilight
  settings are enabled) and to refer who send the message.
* Added usefull fallback message. This message is shown when using Slack over
  IRC or Jabber gateway, so now the actual ping is readable by those users too.

evewspace/eve-wspace,proycon/eve-wspace,proycon/eve-wspace,mmalyska/eve-wspace,Maarten28/eve-wspace,marbindrakon/eve-wspace,Maarten28/eve-wspace,evewspace/eve-wspace,Maarten28/eve-wspace,evewspace/eve-wspace,marbindrakon/eve-wspace,evewspace/eve-wspace,mmalyska/eve-wspace,marbindrakon/eve-wspace,mmalyska/eve-wspace,Unsettled/eve-wspace,marbindrakon/eve-wspace,proycon/eve-wspace,Unsettled/eve-wspace,mmalyska/eve-wspace,proycon/eve-wspace,Unsettled/eve-wspace,Maarten28/eve-wspace,Unsettled/eve-wspace