veyron/tools/playground: Add response caching to the playground.

Uses an LRU cache (golang/groupcache/lru). Dependent on this CL:
https://veyron-review.googlesource.com/#/c/4253/

Also implements a max size of 65k for both the program and response
size.

Change-Id: Ifabb12fdda543d372377bcda9f6995c02e85fe2f
1 file changed
tree: 68a286acea7f6a7910ff5e6dbcb53e7f74198e99
  1. examples/
  2. jni/
  3. lib/
  4. profiles/
  5. runtimes/
  6. security/
  7. services/
  8. tools/