Peter M. Groen / libmodbus

- change return argument from void to int
- update documentation

Thanks to Karl Palsson.

Enable out-of-source build

Add top build directory to tests. Otherwise modbus-version.h
won't be found during the build process.

Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>

Build fails with -Werror and -Wcast-align on ARMv5 platform

DLL if required.

Thanks to Petr Gladkiy

Thank you Petr Gladkiy

.gitignore updates

Thanks to oldfaber and endrelovas.

Simply run cscript configure.js from the win32 directory to generate
the files needed to create the modbus DLL.

Thanks to Mirko Rajkovaca

Thanks Tobias Doerffel.

It will better to code something such as:
https://github.com/crossroads-io/libxs/blob/master/src/err.cpp

I don't intend to rewrite glib neither :(