Various formatting and group name changes

# Changes #

### index.html ###
- Truncated long group names at 20 characters in group page banner.
- Truncated long group names at 20 characters in group view on dashboard page.
- Fixed the observers link in the created group view.
- Truncated long group names at 15 characters in compare groups view - also, when a group is moved to the top section for comparison, if you hover over a truncated group name a tool tip will popup to show full name.

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### player-view.js ###
- Truncated long group names at 15 characters for the group name breadcrumb in the banner.

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### main.scss ###
- Added an underline on hover to group names on the dashboard view and in the group name breadcrumb in the player view banner.