No longer exits when there is a Socket initialization problem

Fixed

• No longer exits when there is a Socket initialization problem

Added

• Added clone-classes.bash and global-status.bash to help retrieving the code and checking the git status of the Socket class dependency.

Changed

• The Makefiles and xmi files have been modified to use the Socket class files coming from the external/Socket directory.
• The CMakeLists.txt file no longer imposes the -g compilation flag. The user can use -DCMAKE_BUILD_TYPE to build a Debug or Release or RelWithDebInfo release if wanted.