Peter M. Groen / libmodbus

Original patch by Sisyph (eric-paul).

The ID used at init time will be the device ID of the caller and
the server ID in request functions is the target to reach.

This reverts commit df0cf7927249954f15e0aa85b02d21b990fa9af9.
Use <modbus.h> in tests.

- returns -1 on error and set errno
- error recovery system was flawed
- error recovery disabled by default
- remove a malloc

This time the change is definitive :)

- new function modbus_flush
- new names and values for error defines
- finer recovery on error
- merge TOO_MANY_DATA and INVALID_DATA
- stop unit-test-master at the first error
- FLUSH_OR_RECONNECT_ON_ERROR -> FLUSH_OR_CONNECT_ON_ERROR
- more precise tests in unit-test-master

- MAJOR changes to the API (see MIGRATION)
- New unit tests
- Removed TODO list
- Updated NEWS & MIGRATION files

- upgrade to WAF 1.5.3
- smaller WAF scripts
- fix using of modbus.h with WAF
- updated configure.ac and Makefile.am files
- change include paths in test files

- The coil and registers are wrote by the master and not assigned by the
  slave anymore
- The data used to write are the ones in unit-test.h
- The read test is done after the write test

- rename test-master-random => random-test-master
- fix memset
- update README
- add the files to configure.ac and wscript

- s/datas/data/
- the warning is now an error
- add some checks in modbus.c
- add unit tests
- remove the TODO item
- minor 80 columns changes

It's slower to pass non aligned values.

- add some unit tests
- add PRESET_MULTIPLE_REGISTERS support in manage_query()

- cleanups in offset/resp_length vars
- cleanups in comments
- add FORCE_MULTIPLE_COILS in manage_query

- Add some tests for force_single_coil

o illegal data value
  o illegal data address
- Better naming of build_query_basis and build_response_basis
- build_response_basis can be use by response_exception
- Reduce variable declarations
- Close 3 FIXME
- Add a test in unit-test-master

- Major changes to unit-test-master/slave to add 4 tests
- Use new functions to manipulate bits
- Reduce memory usage (allocate only the required space and use
  uint[8|16]_t pointers)

- Separate unit-test-master and test-master-random