Add support for Reactive Shield

[JamzTheMan]

• Add ability to raise shield as a reaction if actor has Reactive Shield feat
• Add hasFeats(actor, featNames) function that can take a string of array of strings as feat names and return if actor has any of the feats
• Refactored AoO & ShieldBlock to new hasFeats function

[Saibot393]

Thank you, i will look through it tomorrow and add it to the next release