Changed syntax of named arguments to func(arg: expr)

git-svn-id: http://svn.code.sf.net/p/angelscript/code@1973 404ce1b2-830e-0410-a2e2-b09542c77caf
Added asEP_ALTER_SYNTAX_NAMED_ARGS to optionally support the previous syntax for named arguments

git-svn-id: http://svn.code.sf.net/p/angelscript/code@1974 404ce1b2-830e-0410-a2e2-b09542c77caf