ChainSaw: remove extra copy of unused sound: ChainSaw/obsolete/startIdle.mp3 exists, so delete ChainSaw/src/embedded_assets/startIdle.mp3.

ShipOdyssey and Chainsaw: add {projectbase}/.settings/com.adobe.flexbuilder.project.prefs with setting to use 4.5.1 version of Flex 4 SDK, so that Craig's new copy of Flash Builder (4.7) uses same build as other development machines, which currently use 4.5.1.  I hope that this new preference file does not cause any problems when added to a project for Flash Builder 4.5.1.