   -  rel: 15.08.2023, Major Update
   -  sum: improved scripting and network functions.
           detail improvements and bugfixes.
   -  CHG: SYNTAX CHANGE: option -keepchain is now active by default.
           this means a chain like
              sfk sel -today mydir +run ... +tell ...
           no longer stops at the 2nd command if no files are found.
           command +run just skips to +tell.
           use option -stoponempty for the old behaviour,
           or set SFK_CONFIG=stoponempty
           the new default allows to use
              sfk sel -today mydir1 +sft server cput
              +then sel -today mydir2 +sft server cput
           without stopping inbetween because mydir1 has no recent files.
   -  add: sfk if ... begin ... +elseif ... +else ... +endif.
   -  add: sfk webproxy, a simple http proxy for analysis
           of traffic, and for routing workarounds.
   -  add: sfk web: option -headerstovar to put received
           http headers into a variable.
   -  add: sfk web: option -headertovar to put content 
           of a single http header into a variable.
   -  add: sfk udpsend: return code support.
   -  add: sfk utoa, wtoa: option -showfail to list
           the input codes which fail to convert.
   -  add: the sfk tcp toolkit, consisting of commands like
           accept, connect, send, receive, to write simple
           tcp test scripts. for info: sfk help tcp
   -  add: sfk list: option -xsize to show mixed size
           infos depending on file size
   -  add: udpdump: option -time to tell receive time.
   -  add: udpdump: support for multiple -[not]from.
   -  add: touch: option -delay=n to wait per file.
   -  add: sysinfo: extended by bool size info.
   -  add: help color: SFK_COLORS shortcuts b and w.
   -  add: sfk sleep: support for 1s[ec], 1m[inute].
   -  add: sfk batch: improved function templates,
           extra perline template.
   -  add: sfk samp c tmp.c: full rework of template code
           for an instant c or c++ program, including
           basic tool functions.
   -  add: sfk help env: list supported environment vars.
   -  add: sfk encode -base64: option -linechars=n.
   -  add: sfk unsetvar, delete an sfk variable.
   -  add: sfk loop: optional delay time.
   -  add: sfk fjoin: join files with any filename.
   -  add: sfk -var: #(isempty(a)) now tells
           if variable a is not set or empty
   -  fix: sfk perline no longer removes %1 to %9 in text
           when used directly. in a script, these are still
           replaced by parameters given to sfk label,
           which can be changed by -prefix= option. [23531]
   -  fix: sfk treesize: -gb did not work with -quiet.
   -  fix: filter of multiple files: unexpected context.
   -  fix: sfk ip: memory leak when used repeatedly.
   -  fix: sfk ftpserv: now sends a correct error reply
           if client requests a non existing file.
   -  chg: sfk knxdump: support ga1 value up to 31.
   -  fix: sfk knxdump: wrong output with 14 byte text.
   -  doc: sfk stat: fixed wrong example text.
   -  doc: sfk olist: how to view contents of selected
           office files in a folder directly with dview.
   -  doc: sfk view: -office option, view office example
   -  doc: sfk xex: info about overlapping char groups.
   -  doc: sfk call: more details on recursion limit.
   -  doc: sfk basic: infos on slash and quote caveats.
   -  doc: sfk deblank: improved description.
   -  doc: sfk label, call, wtou: improved help.
   -  doc: sfk video: improved example.
   -  dep: deprecated sfk media removed from help.
           joining files should now be done by fjoin.
   -  dep: sfk ... +tif +tcall +fcall +tend +fend
           are deprecated as they are too complex
           and cause errors.
