Prototype of skip list label store

o Naming: SkipListAccessor, *Record, *Cabinet, *CabinetProvider
o New implementation will be independent of AbstractDynamicStore
o Implements head loading, record creation
o Implements updating record value, beginning of next pointer support
o RandomHeightGenerator factored out
o Adds areSameRecords()
o Adds removeRecord()
o Converts findEntry to the new multimap cake and adds context autorelease
o Tests for DefaultMultiMapContext
Implements core skip list operations

o Extracts SkipListOperations interface
o Implements findFirst, findPred, findAll (using new SkipListIterator)
o Implements insertIfMissing
o Implements removeFirst, removeAll
o Introduces cabinet.delete()
o Refactors into subpackages
o Renames *HeightGenerator to *LevelGenerator
Implements basic StoreSkipList

o Adds StoreSkipList, StoreSkipListRecord
o Adds SkipListRecordBase
o Adds RecordFieldSerializer, KeyValueSerializer
o Adds GrowableByteArray and uses it in the StoreSkipList and SchemaStore
o Removes setRecordValue in favor of remove + insert