Log Message:
Update BibTool to 2.65

2.65
* Hash function and value storing for field name mapping during xref
  expansion fixed.

2.64
* New resource expand.xdata introduced to control the
  expansion of xdata references.
* New resource crossref.map introduced to add a field name
  mapping for crossrefs.
* New resource clear.crossref.map introduced to clear the
  field name mapping for crossrefs.
* io.c introduced to contain input and output file parameters.
* Documentation switched to Lua\LaTeX.

2.63
* Omission of the previous release fixed.

2.62
* Combined rewrite and delete bug fixed.
* Minor improvements for the distribution.
* README renamed to README.md to comply with the
  conventions of the GitHub repository.

2.61
* New resource rename.field introduced to conditionally rename a
  field.
* Typedef String for Uchar* and used across.
* Duplicate file doc/bibtool.tex in the distribution tar ball
  eliminated.

2.60
* The field name and other symbols may start with any allowed
  character. Non-alpha characters at the beginning are treated as
  warning only.

2.59
* Fix in print.c to omit an empty line after overflowing lines.
* Fix in print.c to avoid an overflow situation.

2.58
* Library tex_def.rsc extended with the primitives \i and \j.
* The source tar is signed. The key of the author can be obtained
  from pgp.mit.edu.
* Test renamed to test.