fixes #3178
added test for remove
fix checkstyle
moved tests to MapStoreTest
Added a separate delete method for RecordStore
better renaming & cleanup
Merge remote-tracking branch 'hazelcast/master' into map-store-features

Conflicts:
	hazelcast/src/main/java/com/hazelcast/map/DefaultRecordStore.java
applied changes on backport
Merge pull request #3224 from buremba/map-store-features

fixes #3178