Revert "[AE/CA] - ooppps - typo in last commit (note to self - commit on the same host you compiled it)"

This reverts commit 1c7791d9cfa51c469c876324ade7b037bf2d391a.
[AE/CA] - fix regression (stuck ringbuffer after 46min, 62min, 180min - depending on the stream setup).
Revert "[AE/CA] - fix a possible overflow in the ringbuffer during readsize calculation (yes we hit this in pvr branch in internalflush - when zapping channels)"

This reverts commit e447c4bb34bbc10e1a97ea779eaaafd54a76e3f7.
[CA/AE] - fix race in 2 threads consuming the ringbuffer (dvdplayeraudio calls flush and ca thread still pulls frames) by moving the flush to the ca thread instead - fixes crashing when switching tv channels (this was the real issue the 2 reverted commits before wanted to fix...)
Allow FreeBSD to choose AE Engine
Merge pull request #3156 from Memphiz/fixcaconsumers

[AE/CA] - fix problem where 2 threads read from our lockfree ringbuffer which is not allowed
settings: fix listing of invisible categories and groups