Runs examples with C++ platform description
*Loading platform
- Generates library files for C++ platforms. They can be loaded by the
engine using the same load_platform method.
- The Engine::load_platform will verify if the extension is .so, it'll
open the file using dlopen and search for the load_platform symbol.
- The platform so must contain a load_platform function that will be
called by the engine to generate the platform properly.
*Implementing an example
- Added a CMakeLists.txt in examples/platform to generate the .so for
each example.
- Pass to the tesh files a new variable "libdir" containing the
directory where the libraries are located.
