add Packed8ThreeBlocks
add Packed16ThreeBlocks
relocate packed64 code
add Packed64
decouple interface using Go style
add missing methods
fix compile error
explicit format conversion
fix compile error
hide writer functions
fix compile error
use int32 to sort
fix compile error
move fst to util package
add missing constants
add read bytes buffered method
add simple unit test
consolidated IndexInput as interface; fixed BufferedIndexInput impl
test ReadBytes()
add testEOF()