----------------------------------------------------------
Biddy is based on BDD package written in Pascal in 1992.
That BDD package was later rewritten in C and become an
integral part of EST package, a prototype tool for formal
verification of concurrent systems.

In June 2007, BDD package in EST has been renamed to become
Biddy v0.9. Afterwards, it was completely reorganized and
Biddy v0.99 was built as a standalone module. Biddy v1.0a
was the first one, which was also distributed separately
from EST.

Biddy is used by:
- Bdd Scout (http://lms.uni-mb.si/biddy/)
- EST 1st Edition (http://lms.uni-mb.si/EST/)
- EST 2nd Edition (http://lms.uni-mb.si/EST/)
----------------------------------------------------------

Biddy v0.9, was integrated into EST 1st Edition v1.4
released on Jun 13, 2007 and EST 2nd Edition v4.5 released
on Jun 11, 2007.

Changes v0.99 versus v0.9
- integrated into EST 1st Edition, 1.5 (Jul 19, 2007)
- integrated into EST 2nd Edition, 5.0 (Oct 18, 2007)
- Biddy is now a minimalistic set of functions
- relop, output and many other functions has been removed
- all removed functions has been added to EST project
- Biddy_Boolean, Biddy_String, Biddy_Variable, Biddy_UserFunction, and
  Biddy_Edge are now the only exported data types
- biddy_termTrue, biddy_termFalse, and biddy_termNull are now
  the only exported variables
- variable table is used instead of symbol tree
- makefiles simplified
- macro Biddy_Cmp renamed to Biddy_isEqv
- macros Biddy_isTerminal and Biddy_isNull added

Changes v1.0 versus v0.99
- Biddy is now distributed as a separate package
- version v1.0a released on May 15, 2008
- version v1.0b released on Jun 4, 2008
- version v1.0 released on Jun 18, 2008
- version v1.0 updated several times in 2009, 2010, and 2012
- version v1.0 last update on May 21, 2012
- field "new" in struct BiddyNode renamed to "list"
- calculating the depth of a BDD fixed
- source code cleaned, now even g++ compiles it without warnings
- makefiles and documentation improved and cleaned
- added Makefiles for Mac OS X
- packaging files changed
- added support for debian and rpm packaging
- fixed error in Biddy_E and Biddy_A (2012 and later, only)

Changes v1.1 versus v1.0
- released on Apr 05, 2013 (updated on Apr 29, 2013)
- Biddy_UserFunction renamed to Biddy_VoidFunction
- biddy_termTrue, biddy_termFalse, and biddy_termNull renamed to
  biddy_one, biddy_zero, and biddy_null, respectively
- blocklist renamed to blocktable
- added (but not used) List of fortified nodes
- Biddy_Variable and biddyCount are now only 16 bit long
- Biddy_Edge is now just a pointer instead of structure
- BiddyNode optimized, it is 24B (instead of 36B) on 32 bit systems
  and 48B (instead of 64B ) on 64 bit systems
- some code optimized for new representation of Biddy_Edge
- fixed counters, use unsigned int or unsigned long int instead of int
- improved implementation of Biddy_ITE
