New port: comms/snap7

Snap7, through three specialized components: Client and the inedited Server
and Partner, allows you to definitively integrate your PC based systems into
a PLC automation chain.

Designed to transfer large amounts of hi-speed data in industrial facilities,
it scales easily, down to small Linux Arm boards such as Raspberry PI.

Hi level object oriented wrappers are provided, currently C/C++, .NET/Mono,
Pascal, LabVIEW, Python with many source code examples.

Very detailed documentation provided.

WWW: http://sourceforge.net/projects/snap7/

PR: 215409
Submitted by: vova@fbsd.ru