[TIMOB-10567] Ti API: Expose EXIF data of an image through Titanium API

This ticket stems from the architecture discussion for https://wiki.appcelerator.org/display/eng/Architecture+Proposal+-+Add+orientation+property+to+image+view+and+add+functionality+to+expose+EXIF+data The exif data of an image will include information that may be helpful for users to have during app development. This includes things like orientation of the image, geolocation for the image etc. We want to allow users to get this data given a particular image. This first step in this task is to decide on how we would like to expose this. There have been ideas of including it in an image blob, or creating a separate proxy for the exif data. We need to discuss which properties we want to expose, how we want to expose them (getters/setters vs a single getAttribute() method with attribute constants), and other details regarding how the API will look like.