Making target of assignment explicity with "this".

	modified:   wmserver/world_model_server.cpp
Fixing reference to memory that potentially becomes invalid.

Also some incidental cleanup; moving the current snapshot function
into the base class to save code and simlify code in derived
world models.

	modified:   ../implementations/mysql_world_model.cpp
	modified:   ../implementations/sqlite3_world_model.cpp
	modified:   ../libwm/include/world_model.hpp
	modified:   ../libwm/src/world_model.cpp
Fixing some indentation.

	modified:   ../libwm/src/standing_query.cpp
Adding some comments into the cmake config file.

	modified:   ../CMakeLists.txt
Removing debugging statements.

	modified:   ../libwm/src/standing_query.cpp
Cleaning up the test program.

	modified:   ../tests/src/test_world_model.cpp