find_op_offsets reads the output of the cs command to determine
the number of chain operators from the setup file, then adds 
two for the volume and pan operators, to give the index offset
for the first user effect.

Here is the relevant line from the 'cs' command output:

	Chain "1" [selected] "Channel copy"
		
we will count the quotes, divide by two, and subtract one (for the chain id)
to get offset. Then we add two for volume and pan. Finally, we will
add 1, since perl arrays (used to represent chain operators) are indexed
starting at 0, whereas ecasound indexes operators starting at 1.

In this example, the first user effect will have an index of 4, which
will also be the offset needed for our start-at-zero array.