Yarp rfmodule plugin

[aerydna]

The following pr adds the new type of plugin RFModule.

After including RFModuleFactory.h and creating an instance of RFPlugin will be possible to load dinamically or statically an RFModule calling RFPlugin::open(string commandline).

On the other side, to generate an RFModule plugin will be enough to use the usual yarp_prepare_plugin and yarp_add_plugin macro

The purpose is to give the possibility of running existing modules in a single process contest.

[aerydna]

i don't know why, but for some reasons the pr is not aligned with the branch on my remote. In particular a file was renamed from yarp_plugin_RFModule.cpp.in to yarp_plugin_rfmodule.cpp.in but in this pr exists both version.

i suspect the problem to be related to the warning on [https://help.github.com/articles/about-pull-requests/](this page) wich says When pushing commits to a pull request, don't force push. Force pushing can corrupt your pull request.

the fact is that i didn't push on the pull request branch (in origin) but on the one on my remote and reading the statement isn't clear on which branch is forbidden the force push.

[drdanz]

Can you please add a dummy example that implements an RFModule as plugin?
It would be really useful for reviewing the PR.

[drdanz]

@aerydna ping. This PR is in a pretty good shape, but it still needs documentation and examples, do you think you can find some time to take care of that?

[Nicogene]

Please fix the changelog.

[aerydna]

i'll try to find some time for finishing the pr but i cannot guarantee when i'll do it. it may be postponed to late november for the examples part. other stuff are quick

[Nicogene]

LGTM

[drdanz]

Rebased and updated copyright.

[drdanz]

LGTM