[PROPOSAL] Changes to cache key and cache key management

[Leif Hedstrom]

Hi all,

I wrote up a Wiki about the proposals I have re: TS-1118, to improve the 
cache key system in the HTTP SM. Please take a look at

https://cwiki.apache.org/confluence/display/TS/Cleanup+of+Cache+URLs


Comments and feedback appreciated.

-- Leif

P.s
TL;DR: make the cache keys in the HttpSM much more efficient and flexible, 
and less confusing.