Spice up descriptions of death and rerolls

Fleshes out the text in a couple of modals to be more informative and flavorful. ("Habiteer" is totally a thing, right?)
Groups.html wording tweaks

Fix English syntax in the Tavern for real this time
Mild wording update for new guild buy-in
Move red tasks explanation link inline

Shortens up the message a bit.
Merge pull request #1346 from lefnire/sabe_tweak

Content tweaks
Merge branch 'develop' of github.com:lefnire/habitrpg into develop