Allow to override fluent accessor in generated subclass

[sporniket]

when generating a fluent accessor in a class, and generating a subclass, using the herited fluent accessor cannot be chained to another fluent accessor of the subclass.

allow something like :

<fluent name="xxx" type="yyy">

The name and type MUST obviously match the original definition for the code to be ok.

[sporniket]

As a matter of fact, for the fluent accessor to be really usable, the fluent accessor MUST be overriden when generating a class extending another generated class.

It requires that the generator create an index of the generated classes, and that the fluent accessors are being generated separately.

thus the algorithm in pseudo code :

generateFluentAccessors
    foreach(property in properties)
        generateLocalFluentAccessor(property)
    if(extends and getBean(extends))
        getBean(extends).overrideFluentAccessors

overrideFluentAccessors
    foreach(property in properties)
        overrideFluentAccessor(property)
    if(extends and getBean(extends))
        getBean(extends).overrideFluentAccessors

[sporniket]

requires #16

[sporniket]

The doclet ExpanderDoclet generate separate builder that supporte all declared fields as well as all inherited fields.