New match API added

Added match API to lookup items using partial key (#22)

* Added match API to lookup items using partial key

- minor readability improvement

* RC fixes

Fix type erl_cache:cache_stat/0

• Fix type erl_cache:cache_stat/0 (#21)

Optimise stats collection in erl_cache_server

• Optimise stats collection in erl_cache_server (#20)

Optimise common `get/2` path

• Optimise common get/2 path (#19)

use of Crypto:hash instead of phash

Merge pull request #15 from hmartel/reduce_collision_risk

Reduce the risk of collision when using decorator.

Remove use of lager, support evict_all, bug fixes

• Dialyzer fixes
• Do not use lager (use error_logger directly)
• Add erl_cache:evict_all/1,2 functions
• Fix current memory usage computation in memory usage thresholding
• Various bug fixes