Reduce cost of including chaiscript.hpp

- ChaiScript no longer includes or automatically instantiates std lib
 - ChaiScript constructor now requires an std lib instance in the form
   of a ModulePtr object
 - This new layout facilitates better usage of compilation firewalls and
   factories for reducing the overall impact of ChaiScript on a project

unittests/functor_creation_test.cpp

@@ -1,9 +1,11 @@
 #include <chaiscript/utility/utility.hpp>
 
+#include <chaiscript/chaiscript_stdlib.hpp>
+
 int main()
 {
 
-  chaiscript::ChaiScript chai;
+  chaiscript::ChaiScript chai(chaiscript::Std_Lib::library());
 
   chai.eval("def func() { print(\"Hello World\"); } ");