Added Link for Copying Tour URL to Clipboard

See https://trello.com/c/Tdqava4Z/205-share-tour-link for details.

Added links to each tour in the Tours list that provides a copyable URL
to share the tour. This required adjusting how the message pane on the
left displays.

Also:

1. Tidied up the look of each tour's small blue links.
2. Added tooltips for each tour
3. Renamed the "Tour" link to "View". Now the names of the links are
"View", "Edit" and "Link".