Summoner Archetype: Invoker

[Freeray]

While sharing a name with the defunct summoner archetype, this version is only partially inspired by the old archetype. The other chunk of inspiration comes from the way Yuna's combat is handled in Dissidia. As much as I would have liked to use either High Summoner or Grand Summoner for the name of the archetype, neither seem fitting for a class that losses focus on spells (maybe that means I should think about an archetype that abandons the summon monster class ability for enhanced spell casting...). The way I wrote up the archetype allows some degree of future proofing so the introduction of future avatar choices should not break it.