Swiss File Knife most recent changes

Summary: added clipboard access on desktop linux and mac. copy to clipboard is now faster. detail improvements and bugfixes.

- add: sfk fromclip/toclip on Macintosh, through the pbcopy/pbpaste tool.

- add: sfk fromclip/toclip on desktop linux, through the xclip tool.

- add: "if" now accepts text "1" or "0" to execute or skip the following command or block.

- add: sfk incvar, decvar to increase or decrease the value of a numeric variable.

- add: sfk unzip -asdir x renames the top level folder from a zip file on extraction.

- add: sfk ping: option -noterm to allow writing of ping output to a file.

- add: sfk make-random-file: option -char c to create a file filled with character c

- add: sfk load: option -force to continue script on missing file

- add: sfk calc: -hex to print hexadecimal result.

- add: sfk sft ... putx: alias for put -setexec=*

- add: option -maxsub=n to include up to n subdir levels in commands like list.

- add: sfk knxsend, knxdump: more data types.

- opt: sfk toclip: massive performance improvement with larger data, if -trim etc. options are not used.

- opt: sfk fromclip: performance improvement if following command can receive binary, like xed or xex.

- chg: sfk toclip: now receives binary and text data, to avoid unwanted conversions.

- fix: hexfind: -maxdump was ignored in sfk ose.

- fix: sfk batch vedit.bat: join of videos now works with ffmpeg 4.4.1 or higher

- fix: sfk ... +hexdump -offlen too much output.

- fix: sfk data: symbols like $1foo did not reuse.

- fix: make-random-file: sometimes added LfLf instead of just CrLf line endings.

- doc: more details on -deacc search option.

- doc: alias: xclip example for windows.