try wiki with IndexerInvertedDoconly
fix empty token and empty line for DocOnly
tokenize non-alphabet word cost 4 min without mergeAll
delete everything in index/ before constructIndex
move tokenize from DocProcessor to Utility
DocOnly construct index
remove sth
use Utility.tokenize2 to process query
DocOnly load index ok
DocOnly nextdoc() ok
ranker favorite with index docOnly ok
add first version of index occurence
combine occurence with wiki
work around with : case
run occurence with wiki in 6min
implement getDoc for DocOnly
occurence load index ok
occurence load index ok
simplify occurence
implement occurence with ranker favorite