Fixed the missing check for declaration of duplicate global variables

git-svn-id: http://svn.code.sf.net/p/angelscript/code@1921 404ce1b2-830e-0410-a2e2-b09542c77caf
Implemented C++ operator[] for the CScriptDictionary add-on

git-svn-id: http://svn.code.sf.net/p/angelscript/code@1922 404ce1b2-830e-0410-a2e2-b09542c77caf