Reworded the accept message

Now includes
- a link to the wiki sign up
- a link to the wiki front page for opening times
- directions to us on IRC
Added html version of the acceptance email
Updated the HTML acceptance email

Now has the SMI logo as a header, and tidied up link styles
Added html rejection message
Fixed spacing on changed messages
Readded missing "...
Fixed link
Fixed spaces/tabs
Merge pull request #11 from EdBrereton/master

HTML Acceptance and rejection messages