The Axes class creates and manages axis information and serialization for charts.
should be an axis name like :val_axis and its value should be the class of the axis type to construct. The :cat_axis, if there is one, must come first (we assume a Ruby 1.9+ Hash or an OrderedHash).
provides assiciative access to a specic axis store in an axes
Adds an axis to the collection
Serializes the object If the ids option is specified only the axis identifier is serialized. Otherwise, each axis is serialized in full.