0.20-beta released

Release notes [list] [*] Balance key removed as prerequisite from MixedMysteries -- it does not actually involve the balance mechanic. [*] Fixed break action enablement bug which could result in "breaker on a stick". [*] Altered level MentalMash / CloneBuilder to remove unintended trivial solution [*] Introduced "preferred map order" on load map dialog. This means the game will order incomplete standard maps according to a logical play order in the dialog, hopefully giving a smoother difficulty experience. [/list] josh