[C++] Update of the build

[Christofer Dutz <ch...@c-ware.de>]

Hi all,

I think after 4 days of hard work I have managed to clean up things and now everything seems to be working fine again.
There were several extremely difficult to debug problems I had to solve.
In the end I also addressed the annoying build time problem with the with-cpp profile.

In the end I moved the build of Boost into a separate module (Now located under tools/boost). So if you activate the “with-boost” profile this will be built and it packages the lib and includes directories into a zip.

The plc4cpp build now can take this zip and unpack it into the target directory and use it from there.

Even if it might seem like shifting around things and not really reducing things, it does significantly reduce the build time, as you only need to activate the “with-boost” profile once for every PLC4X version.
As soon as it has been built and installed once, it can be re-used from the maven local repo.

These changes are currently only in the feature/s7-cpp branch.

Chris

PS: @Markus … I saw your branch was almost 200 commits behind develop … so I took the liberty to update your branch to the current state of develop.