Adds WJohnston's rainbow esword and dual-esword sprites.  Also corrected...

... a few bugs involving esword sprites, mainly involving the player sprite not updating when they construct dual-eswords.  It turns out that player-sprite updating is magnets, so the eventual solution was for the player to drop both swords before they're deleted.  Since dual-eswords were already created on the ground, this changes very little.

A dual-esword inherits the emagged state of the esword being attack_by'd.

P.S:  Also added my ckey to the admins.txt for testing convenience.