Xpra

* fix window titles reverting to "unknown host"
* fix tray forwarding bug causing client disconnections
* replace previous rencode fix with warning

* fix client time out when the initial connection fails
* fix shadow mode
* fix connection failures when some system information is missing
* fix client disconnection requests
* fix encryption cipher error messages
* fix client errors when some features are disabled
* fix potential rencode bug with unhandled data types
* error out if the client requests authentication and none is available

* fix modifier key handling (was more noticeable with MS Windows clients)
* fix auto-refresh

* fix transient windows with no parent
* fix metadata updates handling (maximize, etc)

* fix connection error with unicode user name
* fix vpx compilation warning
* fix python 2.4 compatibility
* fix handling of scaling attribute via environment override
* build fix: ensure all builds include source information

* fix avcodec buffer pointer errors on some 32-bit Linux
* fix invalid time conversion
* fix OpenGL scaling with fractions
* compilation fix for some newer versions of libav
* disable OpenGL on Ubuntu 12.04 and earlier (non functional)
* honour scaling at high quality settings
* add ability to disable transparency via environment variable
* silence PyOpenGL warnings we can do nothing about
* fix CentOS 6.3 packaging dependencies