Implementation of MenuBook

Original author: Igor Paliychuk
Don't close other menus when opening books
Merge remote-tracking branch 'upstream/master' into book_patch
Remove triggering books via events
Fix memory leak in CombatText
Merge pull request #1002 from dorkster/book_patch

Implementation of MenuBook
Merge pull request #1006 from dorkster/fixes

Fix memory leak in CombatText