The overriding principle here is to keep the use of AP_Vars as simple as possible, whilst letting the implementation do useful things behind the scenes. To that end, we define AP_Float, AP_Int8, AP_Int16 and AP_Int32. These are strongly typed, so that there is no ambiguity about what a variable "really" is.
The classes behave like the variables they are storing; you can use an AP_Float in most places you would use a regular float; you can add to it, multiply by it, etc. If it has been given an address in EEPROM you can load and save it.
Variables can be given names, and if they are named then they can be looked up. This allows e.g. a GCS or a test tool to find and traffic in variables that it may not explicitly know about.
AP_Var does not attempt to solve the problem of EEPROM address space management.
git-svn-id: https://arducopter.googlecode.com/svn/trunk@1399 f9c3cf11-9bcb-44bc-f272-b75c42450872
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