* removes libircclient from libzetaglest shared library because the
editor and g3d_viewer also link against libzetaglest. Those 2 binaries
don't need libircclient support
* libircclient is now built directly into only the zetaglest binary
* moved libircclient from source/shared_lib because it's no longer part
of the shared library
* libircclient put in dir "external/" because it is an "external" or
"3rd" party library. The @Supertux project does something similar
