Add missing localizations, fix Xcode < 9.3 compatibility, fix Android parity

[hansemannn]

Hey there! This PR attempts to:

• [x] add the missing localizations (#5)
• [x] fix the Xcode < 9.3 compatibility (#8)
• [x] fix the Android parity by passing the consentStatus in the completion handler of consent form

I would also like to add the universal build target (#4) and podspec (#3) if that's something being considered.

P.S.: We already make heavy usage of this SDK in the Titanium bindings, yey!

[hansemannn]

@rampara Are you taking this one?