Opus 1.1.3, w/ framework generator and CocoaPod spec

[iwasrobbed]

• [X] Upgrades to Opus 1.1.3
• [X] Adds framework build support for Swift usage
• [X] Adds easy integration support via CocoaPods
• [X] Adds more detail to the README

[iwasrobbed]

Thanks @chrisballinger

[chrisballinger]

@iwasrobbed thank you! apologies that i didnt notice until now