Lower RES Memory usage!

I got a new Microsoft Surface,  and the memory usage on RES is too much for the poor tablet.  So,  I decided to fork RES and see if I can reduce memory overhead for loading new pages.   If this patch goes well,  I'd like to further reduce RES's memory usage. 

This patch could use more testing.  Loading 10 pages with the current RES takes roughly 804M or ram,  after this patch the page consumed 764M with the same dataset.  Still needs more work,  but there is a noticeable reduction in memory usage with normal browsing habits.

Improvements:
- A bloomfilter is the most efficient way of keeping track of dupes.  A bloomfilter doesn't need to store the full string in order to keep track of uniqueness.  Additionally,  insertion into a bloom filter is always O(1), where as dictionaries need to be expanded when they become full.

-  "Hiding" elements with CSS doesn't make them go away.  These elements need to be deleted properly to free up memory. Hiding elements lead to a **nasty** memory leak.  Reddit has enough re-posts,  there is no need for RES to introduce duplicates to the feed.

I have taken some CPU benchmarks in Chrome, but they are chaotic and I
can't see any difference. (Maybe someone can?)

There shouldn't be a major difference CPU usage when inserting elements
elements between a dictionary and a bloom filter,  because they both have
the same time complexity.  Both a dictionary and a bloom filter rely upon a
hash function, this bloom filter implamentation uses FNV hash (
http://en.wikipedia.org/wiki/Fowler%E2%80%93Noll%E2%80%93Vo_hash_function).
FNV not a cryptographic hash function,  so it is faster than even MD5 or
SHA1.