[Beta] Offline Skill Training Core 0.5a

This was supposed to be in the previous update, but I'm an idiot

The Bookbinder vendor will reward a player when a study book is dropped onto them. The type of reward is gold by default, but I have included comments in the area of the script where this can be changed.

Corrected an issue with preparing to study. In the previous version, you could not un-prepare once you prepared a book for study without logging out and back in. This is corrected - simply double click the book you had previously readied for study.

A study session will now only begin if you log out in town or in a player-owned home.

Created a vendor (StudyBookbinder) that sells a 70-skill version of every study book for 1,000 gold.
Created Standard (70 skill), Advanced (100 skill), and Legendary (120 skill) pre-made study books for easy addition to loot tables, vendors, etc.
Created a Standard, Advanced, and Legendary random study book class for easy addition of randomized books to loot tables.

Files are now in a compressed .zip archive.