Issue #39: wired in CacheWriter stuff.
Issue #39: unit tests for cache writer changes.
Issue #39: added return javadoc for write(K, V, V)
Account for possible multiple mapping function invocations from Store.bulkCompute()
Merge pull request #113 from vfunshteyn/issue-39

Issue #39 - wire cache writer
issue-112: add slf4j
Merge pull request #119 from hhuynh/issue-112

issue #112: add slf4j dependencies