Standardize directory names

Reorganized.  Created a new top level include directory that will hold all of Trick's header files. Moved all of the Trick headers to this directory.  Created a libexec directory that holds all of the executables that users don't need to execute directly.  Changed all of the executables remaining in bin to start with "trick-".  In the sim_services directories changed all source files to find the Trick headers in their new location.  Since all of the include files are gone in sim_services, removed the src directories as well, moving all of the source files up a level.  Moved the makefiles, docs, man, and other architecture independent files into a top level share directory.  Renamed lib_${TRICK_HOST_CPU} to lib64 or lib depending on the platform we're currently on.

refs #63

trick_source/sim_services/VariableServer/VariableServer_shutdown.cpp

@@ -0,0 +1,14 @@
+
+#include "trick/VariableServer.hh"
+
+int Trick::VariableServer::shutdown() {
+    listen_thread.cancel_thread() ;
+    std::map < pthread_t , VariableServerThread * >::iterator it ;
+    for ( it = var_server_threads.begin() ; it != var_server_threads.end() ; it++ ) {
+        (*it).second->cancel_thread() ;
+        // cancelling causes each var_server_thread map element to be erased by the exit_var_thread function
+    }
+
+    return 0 ;
+}
+