fixes #491 and an interesting dlopen/close bug.

fixes #491 by adding a post processing step inside the SqliteBack class's close method. Fixed deprecated doc comment. Fixed segfault issue relating to dynamically unloading of libraries before the event manager recorded its events. The const char* passed to addVal method was trying to access memory that was already cleaned up when externally loaded agents were unloaded.  In short, the module unloading needs to come *after* the final event logging.