Improvements for handling plugins that fail to load.
Improvements for handling plugins that fail to load.

Also improve handling when plugin does not support the number of channels requested.

siddharudh/mlt,xzhavilla/mlt,j-b-m/mlt,j-b-m/mlt,xzhavilla/mlt,xzhavilla/mlt,mltframework/mlt,j-b-m/mlt,xzhavilla/mlt,siddharudh/mlt,siddharudh/mlt,siddharudh/mlt,mltframework/mlt,siddharudh/mlt,mltframework/mlt,j-b-m/mlt,mltframework/mlt,siddharudh/mlt,j-b-m/mlt,mltframework/mlt,siddharudh/mlt,j-b-m/mlt,xzhavilla/mlt,mltframework/mlt,mltframework/mlt,xzhavilla/mlt,siddharudh/mlt,j-b-m/mlt,j-b-m/mlt,mltframework/mlt,j-b-m/mlt,siddharudh/mlt,xzhavilla/mlt,j-b-m/mlt,xzhavilla/mlt,mltframework/mlt,xzhavilla/mlt,mltframework/mlt