* Adds the send_once command and message type, which allows a user to request a variable to be sent immediately and only once (intended to replace the var_add, var_send, var_clear idiom that is commonly used for this purpose)
* Minor refactoring of variable server internals to reduce repeated code
* Adds SIM_test_varserv to integration test to test basic variable server functionality
* Changes graphics client for SIM_billiards to use var_send_once as an example of intended use
* Add documentation for var_send_once in docs and tutorial
* Set exit_code_enabled in trick unit tests to be true by default
* Patch for failing bookworm build
* Add capability to list current variable server connections in JSON ref #678
* Add client tag to the connection info.
* Name consistency tweak in generation of JSON variable-server connection list. ref #732
* Add client IP address and port. ref #732
* Output should be going to the stringstream, not std::cout. Ref #732
Added a flag called validate_address to each variable server thread. When
activated each pointer address will be tested to see if it is in memory
the memory manager is tracking. If it is then everything proceeds normally.
If it does not, then an error return value is returned for the value of this
variable.
refs #193
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
