substantial update of books.msa

* Added /book, /book-publish, /book-list, /book-delete, /book-download, /book-legacy
* Migrated /rulebook, /paste, /edit commands from rulebook.msa to books.msa
* /rulebook now essentially an alias for /book rules
migrated commands to books.msa

* moved /paste, /edit to books.msa
* commented out legacy /rulebook command in favor of new version in books.msa
updated firstjoin to use /book rules
clarifying instructions
Added /book-cooldown

/book-cooldown <minutes>
Allows admins to set interval between players' ability to use /book command.
book and book-delete are now case-insensitive

Changed storage of book list to use associative array with lowercase label as key, mixed case label as value.
/book-list displays the original case form of the book label as entered in /book-publish, and /book and /book-delete can use any cased variant of the label.

Adjusted a few commands to accommodate input mistakes
Rearranged command readout when admin uses /book without arguments. Also changed colors to be easier to read.
Merge pull request #24 from Mumberthrax/master

Overhaul of /rulebook command via /book