Modified the draft's abstract

I modified the abstract pretty drastically (I apologize in advance if I cut out too much). Let me know what you think.

Basically I don't like "attacking" the traditional cache, since I believe that if it has problems, it should be fixed. The reason that the traditional cache doesn't work for cross-site resource sharing is the fact that it is based on a URL, which means it fails once developers use multiple CDNs, etc. This has nothing to do with the cache's eviction policies. So, I modified that part.

Other than that, the examples look interesting. I'll go over them in detail tomorrow.

I'm also not sold on the case for a "repository URL" for the spec(even though we discussed it last time. I understand it's needed for the prollyfill, but not sure if it's useful after native impl). Can you try to explain why it is necessary, and what are its benefits over the CDN approach?