Fix error message into warning
Correct graph drawing for inner pass-throughs

Example:

scatter |{
	# IP/AP channel conversion
	# See http://tech.groups.yahoo.com/group/nmrpipe/message/389
	-| nmrPipe |
	   nmrPipe -fn SOL |
	   nmrPipe -fn SP -off 0.5 -end 0.98 -pow 2 -c 0.5 |
	   nmrPipe -fn ZF -auto |
	   nmrPipe -fn FT |
	   nmrPipe -fn PS -p0 177 -p1 0.0 -di |
	   nmrPipe -fn EXT -left -sw -verb |
	   nmrPipe -fn TP |
	   nmrPipe -fn COADD -cList 1 0 -time |
	   nmrPipe -fn SP -off 0.5 -end 0.98 -pow 1 -c 0.5 |
	   nmrPipe -fn ZF -auto |
	   nmrPipe -fn FT |
	   nmrPipe -fn PS -p0 0 -p1 0 -di |
	   nmrPipe -fn TP |
	   nmrPipe -fn POLY -auto -verb |{
		-||>/stream/A1
		-||>/stream/A2
	|}

	-| nmrPipe |
	   nmrPipe -fn SOL |
	   nmrPipe -fn SP -off 0.5 -end 0.98 -pow 2 -c 0.5 |
	   nmrPipe -fn ZF -auto |
	   nmrPipe -fn FT |
	   nmrPipe -fn PS -p0 177 -p1 0.0 -di |
	   nmrPipe -fn EXT -left -sw -verb |
	   nmrPipe -fn TP |
	   nmrPipe -fn COADD -cList 0 1 -time |
	   nmrPipe -fn SP -off 0.5 -end 0.98 -pow 1 -c 0.5 |
	   nmrPipe -fn ZF -auto |
	   nmrPipe -fn FT |
	   nmrPipe -fn PS -p0 -90 -p1 0 -di |
	   nmrPipe -fn TP |
	   nmrPipe -fn POLY -auto -verb |{
		-||>/stream/B1
		-||>/stream/B2
	|}

	.| addNMR -in1 /stream/A1 -in2 /stream/B1 \
	   -out A+B.sgsh.ft2 -c1 1.0 -c2 1.25 -add |.
	.| addNMR -in1 /stream/A2 -in2 /stream/B2 \
	   -out A-B.sgsh.ft2 -c1 1.0 -c2 1.25 -sub |.
|}