Extend PebblesDB to use SURF filters

[vijay03]

PebblesDB currently uses bloom filters. Change PebblesDB so that it uses SURF Filters from CMU (https://github.com/efficient/SuRF) instead. This should help both point-query and range query performance.

[malavdesai16]

Hello Sir,
It was noted in the paper that using Bloom filters is PebblesDB leads to high consumption of memory compared to HyperLevelDB. I read an interesting paper on Vacuum Filters. Is it feasible to extend PebblesDB with Vacuum Filters? Although, it wont help point-query and range query performance but it will help with minimizing the space consumption.