GiD dynamic library plug-in

This is a particular mechanism of plugin, different of the Tcl-plugin, and it only allows to import mesh and results in postprocess, and require to compile a special dll with our rules.

Note that 'GiD dynamic libraries' are different of 'Tcl loadable libraries'

'GiD dynamic libraries' must do specifically the task that GiD expects: now it is only available an interface for libraries that import mesh and create results for GiD postprocess. In the future new interfaces to do other things could appear, and to be usable must follow the rules explained in this chapter.