DWDS/Dialing Concordance Code

+ tagged ddc-2.2.8-rc1

* proto docs

+ merged branch ddc-2.2.7+prune -r1530:1548 intro trunk:
* added #PRUNE_ASC[N,KEY(s)] and #PRUNE_DESC[N,KEY(s)] filters
- limit response to at most N hits per count-key given by KEY(s)
- only metadata attributes allowed in KEY(s) (because token-attribute key evaluation needs more ConcSession data populated than we have or want)
* overhauled handling of ':'-operator in both branch and leaf servers
- fixes mantis #50057 ; helps workaround mantis #50058
- actually parse queries in CDDCBranchServer during runq.Init()
- updated query parser (:-operator only allowed *after* all other filters, and *not* in count-query daughters)
- updated server protocol: added optional REQPATH before HINT
+ needed for correct evaluation of ** path-wildcards in ':'-operator subcorpus lists
- added CHost::m_ShortName - without 'server:' prefix
- added CDDCBranchServer::m_HostMap - for less painful daughter-selection
- added CRunQueryData::ReqPath - for tracking request paths (for server VersionCompat >= 2.2.8)
* added new server request nodes - return list of all reachable sub*corpus paths ()

+ querydoc updates for v2.2.8 (:-operator overhaul, #prune filter)

* back to qf_subcorpora in q_flag : shouldn't be allowed embedded in count-queries though (-> misleading)

* CheckSatisfiable() implementation for #HAS filters over constant attributes

+ fix request-path parsing & evaluation in branch server

+ various fixes related to :-operator
- added CHost::m_ShortName - without 'server:' prefix
- added CDDCBranchServer::m_HostMap - for less painful daughter-selection
- added CRunQueryData::ReqPath - for tracking request paths (for server VersionCompat >= 2.2.8)
- added new server command "nodes" - return list of all reachable sub*corpus paths ()

+ query parser: qf_subcorpora clause clobbers any earlier qf_subcopora (non-additive)
+ branch server: use parsed query for selecting daughter subcorpora
- syntax works, actual sub*corpus selection is still buggy

+ lexer-level tracking of qf_subcorpora request offset+length