MFC-J430W support

[rumpeltux]

First, great job with this tool! Thank you, I’ve been hating that proprietary driver forever.

I managed to get my scanner to work with minimal modifications as you can see in rumpeltux@0bdfbe4
(not sure that patch is the right way to approach the problem, but it did the trick for me)

Essentially the message sent by my scanner looks like this:

0040 … … 00 1a 00 31 30 30 2c 31 30 30 2c 32 2c 32 .....100,100,2,2
0050 30 39 2c 38 32 36 2c 32 39 34 2c 31 31 35 37 09,826,294,1157

So there’s no trailing 0.

Another example (this time from ADF, thus no limit on image height):
{
00000000: 3014 0046 3d46 494c 450a 443d 5349 4e0a | 0..F=FILE.D=SIN.
00000010: 453d 5348 4f0a 80 | E=SHO..
}
{
00000000: 1b49 0a44 3d53 494e 0a4d 3d43 4752 4159 | .I.D=SIN.M=CGRAY
00000010: 0a52 3d31 3030 2c31 3030 0a80 | .R=100,100..
}
{
00000000: 0015 0031 3030 2c31 3030 2c31 2c32 3039 | ...100,100,1,209
00000010: 2c38 3236 2c30 2c30 | ,826,0,0
}
{
00000000: 1b58 0a41 3d30 2c30 2c38 3236 2c30 0a42 | .X.A=0,0,826,0.B
00000010: 3d35 300a 433d 4a50 4547 0a44 3d53 494e | =50.C=JPEG.D=SIN
00000020: 0a47 3d31 0a4a 3d4d 4944 0a4c 3d31 3238 | .G=1.J=MID.L=128
00000030: 0a4d 3d43 4752 4159 0a4e 3d35 300a 523d | .M=CGRAY.N=50.R=
00000040: 3130 302c 3130 300a 80 | 100,100..
}

[rumpeltux]

This should be addressed by #6 more correctly now.