Make taut buff default behaviour

[Galaco]

Overview

Removes the skill Taut from the skill tree. The debuff that humans experienced without have Taut has been removed (aka Taut is applied to all humans).

Resolves #21

Demo

Notes

Testing Instructions

• Join the server
• Take a hit from a zombie, while holding a prop (or as a zombie, hit a human holding a prop)
• You (or the opposing player) should not drop the held prop on receiving damage

Checklist

• [x] fixup! commits have been squashed
• [x] README.md updated if necessary to reflect the changes