DWDS/Dialing Concordance Code

+ tested count-keys queries: seems ok

+ added default server options file etc/ddc_server.opt
+ raised SlowQueryTimeout to server-options level
+ report active server options in ddc_daemon on server startup

* added debug-log (notes)

+ wrap dangerous locked index sub-object code in try/catch to avoid deadlocks on weird exceptions (e.g. std::bad_alloc)

* local locks in low-level index sub-objects seem to allow us to omit session-context lock in CConcSession::GenerateHitStrings() -- yay! ; test script reports Amdahl P > 99% for N=4 and simple @-queries; P ~ 80% for CAB-expanded queries

+ local locks in m_pIndexator sub-objects (CStringIndexator, CConcXml, CIndexSetForQueryingStage via new ddcLockable base-class (simple single-lock object) -- simple parallel @-queries seem to work now

+ client-threads debugging: 99% working with locks in GenerateHitStrings(); hard to reproduce errors

+ client-threads work in progress: clone term expanders (b/c curl handles can't be shared)
- tests with @-queries often show 100% expected responses
- expected responses as low as 29% for -n 32 -i 128 : something is still foul

+ refactored old ConcHolder.* into ConcSessionContext.*, ConcSession.*
- ConcSessionContext: shared global data (cache)
- ConcSession: thread-local data (everything else)
- ConcHolder: now just a typedef alias for ConcSession

* factored out QueryResult, CQueryResultIndex from ConcHolder.h to new QueryResult.h