Add find-replace syntax for cligen/argcvt.argParse(string)

Also some slight enhancement to printedLen & printedChars for unprintable ASCII and some minor ""-safety fix ups.

RELEASE-NOTES.md has more details & git log max details.

Minor bug fix release

Address problem in rare cases where open() succeeds, but read() immediately fails.

Minor API updates

Release notes have more details and git log full details, but mostly just cligen/mslice.join/find, a new strUt.nearUnity4, and an fcvt bug fix.

Rename `sysUt.!` to `sysUt.!!` for various reasons

Mostly this is much easier to in-file search for (no collision with != or comment text), but also emphasizes the operator better which is helpful since it is a control flow operator.

utf8 bugfix; SGR/ANSI color code Update; Helper Libs updates

Subject is a pretty good "summary". The bug fix was for iterator printedChars on strings ending in multi-byte utf8. The SGR updates are renaming conceal -> hid and adding over and -fg, -bg with similar updates in python/cg.py and a new textAttr shorthand. The helper lib updates are a few mods/adds to cligen/sysUt and deprecation of the always questionable sysUt.findUO. RELEASE_NOTES.md has more details and git log max detail.

--help-syntax default text improvement; textUt improvments; Warning silence

That's a pretty good summary. RELEASE-NOTES.md has more details and the version control changelog all details.

Dependent packages should not feel compelled to upgrade unless their users complain about --help-syntax or lack of "overline" or "-fg -bg" kinds of SGR codes.

Add cg.py for Nim refugees in PythonLand; Add `writeContAddrTempFile`

See python/cg.md for some preliminary documentation.

python/cg.py is quite incomplete relative to cligen.nim, but it does the basics of what I need right now to not feel CLI framework-impaired when there is some Py lib/ecosystem I want to write a quick script around.. python/pq.py is a full usage example in the rp / crp family of awk imitations.

Also add the almost never supported SGR attribute conceal & its negation -conceal and a little utility function cligen/osUt.writeContAddrTempFile

Just to make the VC tip a clean release after init syntax thrash

That's it.

Default-default-value controls, $usehdr & ClCfg.(wrap(Doc|Table)|subRowSep)

RELEASE_NOTES.md has details as usual, but controls for how string & bool default values are rendered in help messages have been added to ClCfg for CLauthor default-setting with CLuser override in config files.. basically minStrQuoting, trueDefaultStr, & falseDefaultStr. These were, of course, always alterable via defining custom argHelp, but this tunability shouldn't impact non-users-of it. Also added $usehdr for the main usage template, ClCfg.wrap(Doc|Table) and abstract the old newline-only separator into ClCfg.subRowSep and fix an old bug related to ignoring the CLuser use|usage template.

In short, basically several new fine-grained format controls.

Very minimal change to config file finding

See RELEASE_NOTES.md and git log -p. Really should be just an internal simplification, but I wanted to make this its own release just in case.