leptonica: updated to 1.84.1

1.84.1
* Remove support for openjpeg versions < 2.1.
* Improve error handling for stringLength() and stringCat(), and
  add tests in prog/string_reg.
* Source files changed: blend.c, dnafunc1.c, jp2kio.c, pageseg.c,
  partify.c, pix1.c, ptafunc2.c, sarray2.c, utils2.c
* Prog files changed: boxa3_reg.c, string_reg.c, writetext_reg.c,
  deskew_it.c

1.84.0
* Add getPdfPageCount() to find the number of pages in a pdf file.
* Add getPdfPageSizes() and getPdfMediaBoxSizes() to find the
  information necessary to render images properly.  Modify cleanpdf.c
  and concatpdf.c to use this information.
* Add prog/splitpdf.c to split a pdf file into nearly equal page sets.
* Add ability to read and write rgba in bmp format, and
  test in ioformats_reg.
* Add regression test prog/partition_reg.c
* Change the autotools library name from liblept to libleptonica,
  to be consistent with the cmake library name.  (Apologies to Jeff!)
* Add tests for 24 bit pix reading and writing in bmp and png in
  ioformats_reg.  Test new pixDisplayDiff() for visualizing diffs.
* Allow prog/concatpdf to output pdf with tiffg4 encoding and with
  mixed tiffg4 and DCT encoding depending on image color content.
* Rename prog/concatpdf --> prog/compresspdf
* Put image processing and generation of output pdf from compresspdf
  and cleanpdf into functions in new files: pdfapp.c, pdfappstub.c.
* Add versatile function for cropping an image and filling to
  page size, along with prog/croppdf to do this on pdf file.

(adam)