Add several TIFF decoders and encoders

[megabuz]

libtiff can work with many tiff compressions, such as deflate, adobe deflate, sgilog and others. So we can add this functionality such as group4 decoder/encoder

[aclark4life]

Any risks merging this?

[megabuz]

i can't find libtiff release notes, so i don't know when they add this compressions types, but i think, it is old functionality

[megabuz]

Found release notes, everything ok. I don't see any risk

[aclark4life]

Thanks all

[wiredfool]

The only danger I can see is that some of the full color tiff compressions can have an awful lot of data behind them, and when going from an in-memory string, it's an all at once thing. So, memory exhaustion could be an issue.

(Also, might want to check on some signed/unsigned things, I'm not sure if there will be issues if we get something that's over 2 gig uncompressed)