src/lse/engine.cpp: be explicit in usage of the window member of Engine; we also move a try catch block out farther so we can hopefully catch all errors generated in the main thread

  - clean up an unsigned int/int conversion problem in debug/main.cpp
src/lse/thread.cpp: add a catchall exception handler to Thread.thread_method so hopefully threads don't die off without is knowing (and also the exceptions don't go uncaught and crash the program)