First pass at adding param callbacks via binded accessor functions.
Added param with callbacks to ParamBasic sample.
Removed unused variable pointer. (Much more sensible!)
Simplified sample and removed auto to void ambiguous call errors.
Use light direction vector for Params callback demo.
added initial params::ParamsBase, Param<T>
added accessors
added updateFn()
added other types that are in the pre-existing interface
added missing types that ATB currently supports
added step
moving towards addParams() that returns Options<T>
Added precision.
Merge pull request #418 from num3ric/params_named

Added precision.
largely shuffling around and organizing private impl methods versus private anonymous methods
addParamCallbackImpl that takes Options<T>. Requires storing the optional val's as they are called so they can be re-added
improve memory management: using map<name, shared_ptr<void> > instead of list of callbacks, removing old callbacks
added Options<T>::optionsStr() for anything not covered by other methods
Clarified the usage of accessors by giving it a new public addParam( name, setter, getter ). Is still routed through the other addParam<T> method.
doxygen, other cleanup