implement PendingBlock.compileIndex()
implement TermsWriter.writeBlocks()
implement TermsWriter.writeBlock()
implement TermsWriter.writeBlock()
implement PendingBlock.compileIndex; fix NPT
implement FSTEnum.doNext()
implement PerFieldPostingsWriter.addField(); implement FST.readFirstTargetArc()
fix incorrect field number
enforce key order during serialization
fix empty numeric norms
fix incorret value