fix PostingFieldReader and add DocValuesReader
add StoredFieldsReader and compressing related logic w/o real implemenations
4.4 fix class name
4.4 fix class name
move to 4.4
include TermVectorsReader without impl
refactor Directory and LockFactory as interface
refactor Directory as interface
fix pointer reference
refactor TermsEnum as interface and SegmentTermsEnum; fix compile error
fix list remove
fix compile errors for index package
pass search package build
force IndexReader and IndexReaderContext as interface
remove unnecessary self pointer
add search test; fix IndexReader/IndexReaderContext as interface