Customizable script to allow honor from creature kills

* See CONF section: CUSTOM SERVER OPTIONS - CREATURE HONOR
* For existing servers, please import: characters_create_creaturehonor_message.sql
* Made a change to CMakeLists.txt which allows inclusion of custom scripts. Re-run CMake if you're not starting fresh.
I made the change but I was always of the mindset that if you don't really need to use the string then by value is the way to go since using *const std::string&* causes VC++ 11 to allocate memory to copy the string when it is used.

[This](http://stackoverflow.com/questions/10231349/are-the-days-of-passing-const-stdstring-as-a-parameter-over/10232761#10232761) is one of the references I looked at when trying to decide.