Interfaces' cmake cleanup (step 2)

[varhub]

Interfaces step 2: cleanup due it is working without any problem

Completes #237

• cleanup interfaces' cmake
  • remove rollback code maintained since Outsource build (2): interfaces + gazeboserver/plugins #237
  • remove ugly dummy_main.c approach for headers trick

Breaks target install convection

move slice files from include/jderobot/slice to share/jderobot/slice
This is the way to go because slice files are auxiliary files and do not interact with cxx compilers. So there was two options:

1. install belong generated headers to ensure C++ coalescence
2. remove from include because current path do not fit Linux's include/ policy.

(2) was chosen because (1) is dirty with the current policy for headers.

Advice for visualHFSM

@reysam93, I must change a little piece of visualHFSM. Therefore this PR should be merged if and only if you approve it.
By the way, you should change this call because hardcored paths are not recommended.
Recommendation:
jump to system("./getinterfaces.sh) and put static paths at sh file. Why? because change paths can be done at runtime and do not require rebuild.
Eventually this can even jump to system("getinterfaces.sh) and patch PATH inside cpp to add '.' directory. Therefore, /usr/local/bin/getinterfaces.sh (if it is planned to be installed) will be callable and allow execute visualHFSM out of the box.

PS: I suspect that @jmplaza must also approve it.

[fqez]

Ok then. I'm not touching this until both @jmplaza and @reysam93 confirm this can be merged.

[fqez]

I close this PR because is so ancient. If you want to return on developing this particular issue, let me know and I will reopen it!

Cheers!