Added support for logo branding in the lower right corner of the client

bigbluebutton-client/.actionScriptProperties

bigbluebutton-client/.flexProperties

bigbluebutton-client/.gitignore

...ebutton-client/.settings/org.eclipse.core.resources.prefs

bigbluebutton-client/src/branding/css/assets/img/BBBLogo.png

bigbluebutton-client/src/branding/css/theme.css

...client/src/org/bigbluebutton/main/views/BrandingLogo.mxml

...rc/org/bigbluebutton/main/views/MainApplicationShell.mxml