DWDS/Dialing Concordance Code

+ lexer-level tracking of qf_subcorpora request offset+length

+ fixed run_query error formatting in leaf server

+ fixed run_query error formatting in branch server (e.g. on exceptions from runq.Init(), including parse errors)

+ #prune[] implementation seems working as well as can be reasonably expected on tiny test corpus

+ track raw byte-offset in yyQLexer

+ parse queries in branch server during runq.Init()

+ #prune[] filters appear to be working on leaf-level

+ #prune[] filters: fixed double-free segfault

+ #prune[] filters: lexer, parser, toString()

+ #prune[] filters: basic types