Add pseudo-constant copies of the AP_Meta_calss::Type_id for the standard AP_VarT subclasses. This makes checking the type of a possible AP_Var much cheaper than calling ::meta_cast, as there is no object con/destruction involved.
Add some helper functions for manipulating AP_Vars from Menu interfaces.
git-svn-id: https://arducopter.googlecode.com/svn/trunk@1541 f9c3cf11-9bcb-44bc-f272-b75c42450872
DrZiplok@gmail.com