Added X11 error handling functions to FMXExternalPumpBrowser2 demo for Linux.
Deleted FMXExternalPumpBrowser demo for Linux.
Added uCEFMacOSConstants and uCEFMacOSFunctions units for MacOS.
Replaced TThread.Queue for TThread.ForceQueue to avoid executing that method immediately in some cases.
- Added TCEFWorkSchedulerQueueThread as an experimental way to handle the external message pump events for all platforms.
- Fixed backwards compatibility issues with Delphi 7.