changed the external hash join
add OperatorScanFlt, changed several names of files
prepare for check point3, fixed input arguments for Main
close debug mode
delete print time switch of Config
a little change for sanity check,  comment print msg
111
bug need to fix
fixed a bug of Datum compareTo()
add IndexManager
test for check point3 after server bug fixed
test for cp4
changes a little for cp4
test for dropbox
include new files
finish cp4
changes for query06