Big refresh & refactor, add wdscheme -t, use 0BSD

* add wdscheme -t to set shell-local scheme override
* refactor: dedupe and use internal functions more often
* fix: `install.sh` pointed to old README
* improve `install.sh` instructions and hygiene
* remove extra loop in `wdl` for bash, matching zsh
* quote and escape all var expansions
* modernize CHANGELOG to markdown, ISO dates
* add note about using `direxpand` for bash
* remove old TODOs that won't work (mostly due to inconsistency
   between env vars, aliases, and persisted slot values across shells.)
* Switch to 0BSD License
* Fix i var leaking and env var staleness

CHANGELOG.md

@@ -0,0 +1,71 @@
+### 3.0 - 2021-10-03
+* add wdscheme -t to set shell-local scheme override
+* refactor: dedupe and use internal functions more often
+* fix: `install.sh` pointed to old README
+* improve `install.sh` instructions and hygiene
+* remove extra loop in `wdl` for bash, matching zsh
+* quote and escape all var expansions
+* modernize CHANGELOG to markdown, ISO dates
+* add note about using `direxpand` for bash
+* remove old TODOs that won't work (mostly due to inconsistency
+   between env vars, aliases, and persisted slot values across shells.)
+* Switch to 0BSD License
+
+### 2.2 - 2019-09-26
+* Improve zsh support
+
+### 2.1 - 2010-13-11
+* rewrote file reading with advice from Wayne Seguin
+* reformatted and fixed some code style issues
+
+### 2.0 - 2010-20-10
+* completed single-file, pure bash rewrite (no longer needs perl)
+* env. vars now auto-update
+* clear a single slot with a dot: `wds3 .`
+
+### 1.12 - 2010-06-10
+* Hosting on github
+* Updated README
+* zsh compatibility fixes by Matt Fletcher
+
+### 1.11 - 2004-19-03
+* fixed wdenv bug with spaces in dir names
+* added bash completion to `wdscheme`
+
+### 1.10 - 2004-24-02
+* fixed quoting in `wdaliases.sh`
+* fixed `WDSCHEME` usage for local scheme use
+* released to sourceforge.net
+
+### 1.09 - 2003-12-03
+* added Gary Cramblitt's man page
+* fixed install script for Solaris
+* fixed bug when passing a dir. to `wds`
+* updated `readme.txt` a little
+
+### 1.08 - 2003-11-19
+* fixed `wdscheme.pl -s` check (thanks Dave and Frank!)
+* now effectively enforces 10 lines in all commands
+* copies readme.txt to dist dir on install
+
+### 1.07 - 2003-11-16
+* fixed `wdenv` by making it a separate script as well
+* made `wdenv` only export slots that are filled
+* actually removed `wd.list` and `wd.dest` (from CVS too :)
+
+### 1.06 - 2003-11-10
+* made `wdl` a script instead of a plain alias
+* wdscheme now unsets WDSCHEME
+* fixed tarball root dir
+* updated readme
+* made all scripts use new `wdscheme.pl` for figuring the current scheme.
+* removed unused `wd.list` and `wd.dest`
+
+### 1.05 - 2003-11-08
+* made recall of empty `wd` entry not `cd`
+* better error handling of schemes deleted while they are active
+* removed `WDSCHEME` env var from default script use (still checked
+   on recall, for manual override)
+
+### 1.0 - 2003-10-01
+* initial release