c-treeSQL Server System Signal Handling

When CONSOLE CTRL_C_ENABLE is specified in the c-treeSQL Server configuration file a <CTRL>-C key combination or the SIGINT signal should begin a normal server shutdown process. It was found that the c-treeSQL Server ignored this signal as well as the SIGQUIT and SIGTERM signals. Proper signal handling has been enabled on the c-treeSQL Server such that correct operation is restored for this useful c-treeSQL Server configuration option.