Reconstruct the file format in the file metadata (#90)

* add new metadata format

* add new API for row group block metadata

* Clustering RowGroupMetaData and computing the timespan

* change row group block metadata api

* fix one bug

* Use an LRU list to manage deltaObjects within a file.

* re-add RowGroupReaderList for compatibility

* fix write bug

* fix bugs caused by lazy read

* Fix a bug that causes adding duplicate RowGroupReaders to a RecordReader

* Add api for DeltaObject and Measurement existence in FileReader

* Add RowGroupBlockMetaData Time Test

* make the test class of RowGroupBlockMetadtaTimeTest not avaiable

* compatibility for IoTDB

* set delta_object_id in RowGroupBlockMetaData optional

* modify FileReader,ValueReader

* add close method in RowGroupReader

* make version SNAPSHOT

* add time encode plain test

* make time encode TS_2DIFF

* fix bug in OverflowTimeFilter

* change tsfile version and magic words

* changed Naming style in tsFileIOWriter

* Formatting code in tsFileIOWriter