mustella.swc is only built if it either doesn't exist, or any of the .as files in as3/src/mustella changed (will not detect changes in included assets).  Also moved where some properties are set so they are set before they are used.
mustella.swc is only built if it either doesn't exist, or any of the .as files in as3/src/mustella changed (will not detect changes in included assets).  Also moved where some properties are set so they are set before they are used.

git-svn-id: 7d913817b0a978d84de757191e4bce372605a781@1381397 13f79535-47bb-0310-9956-ffa450edef68

shyamalschandra/flex-sdk,SlavaRa/flex-sdk,shyamalschandra/flex-sdk,danteinforno/flex-sdk,apache/flex-sdk,SlavaRa/flex-sdk,apache/flex-sdk,danteinforno/flex-sdk,adufilie/flex-sdk,SlavaRa/flex-sdk,apache/flex-sdk,danteinforno/flex-sdk,SlavaRa/flex-sdk,SlavaRa/flex-sdk,apache/flex-sdk,adufilie/flex-sdk,shyamalschandra/flex-sdk,shyamalschandra/flex-sdk,adufilie/flex-sdk,shyamalschandra/flex-sdk,adufilie/flex-sdk,danteinforno/flex-sdk,adufilie/flex-sdk,apache/flex-sdk,adufilie/flex-sdk,SlavaRa/flex-sdk,shyamalschandra/flex-sdk,danteinforno/flex-sdk,danteinforno/flex-sdk,apache/flex-sdk