DWDS/Dialing Concordance Code

+ added jemalloc follow-up observations to change-log

2018-08-21 added new command-line utility ddc_split, using ConcordLib/ConcordSplit.cpp
- partition a single physical index into N subcorpora of roughly equal size
- as for ddc_union, user can also specifiy a target *.opt file to select specific indices and/or bibl attributes for output

+ removed old binary ConcordUnion stuff
+ added ddc_split (guts still todo)

+ ddc_union: sanity checks for bibl constants

+ ddc_union tweaks for translation maps (use vector instead of map)

v2.1.15-pre1:
* 2018-08-17 added new command-line utility ddc_union
- based loosely on old ConcordUnion.cpp code (and the code it calls)
- ConcordUnion.cpp & friends supported only binary union operations, and no option-modification (e.g. MaxTokenCountInOnePeriod)
- new code supports n-ary union including option update and target attribute selection (via -O option)
- old code was apparently never called (and was broken in some places), and should probably go away now

IndexSetForQueryingStage.h: removed EndOfSentenceForBigrams flag from CIndexItem::m_IndexItemOffsetAndFlags

+ ddc_files.pod update

+ ddc_files.pod link fixes

+ ddc_server.opt: added minimum version for HitStringsParallel option