Log Message:
leptonica: updated to 1.78.0

1.78.0:
* Various improvements in handling boxa sequences and transforms.
* New regression tests: boxa4_reg, string_reg
* New function for copying a pix, filtered by a boxa.
* Modify histogram method for image comparison.
* More careful attention to invalid boxes in box geometry functions.
* Better string and array functions for search and replace.
* Convenience functions for generating simple masks.
* Allow pdf writing of jp2k images, in full generality.
* Allow writing compressed ps images for printing.
* Modified enum comments to include a suggested enum name.
* New program: imagetops