[Cin] ChromakeyHSV menu much improved

[Igor BEGHETTO]

Thank you so much, Georgy_Salnikov, for the new ChromaKey(Avid) plugin!
I have not applied the patches and not used the new plugin, yet. As soon 
as I will do.
Good idea to have the new plugin without to touch the others for 
compatibility with older Projects.

And I would like to thank Igor_Vladimirsky for the great explanation on 
that, in his blog/manual;
and to thank the programmer, Adam Williams, who  implemented this 
feature on Cinelerra-HV.

And thanks to Andrea_paz, for insiting on some features and the Manual.
;-)

IgorBeg