Revert "Fix text decoder length option"

This reverts commit 05f78e5b7f4ad0454f15d270a47a092dedddde88.
Revert "Update gemspec"

This reverts commit 541f68108fab0edb5f36ba20151c3a08de064cdc.
Revert "Add support for decoding via OCR"

This reverts commit 4338121bedb07ac5d6da7ae46e78d8ab8639e617.

OCR is not a good idea for our purposes as characters such as '0' and 'O' are
too easily confused.
Update gemspec