Keep TiddlyWiki client code local to this repo

More findable.
Make README markdown
Update README

* more info
* pointers to documentation
* markdown
* friendly tone(?)
Get rid of out of date dox
Keep tiddlywiki resources local and update to pass tests

this includes the empty.html, currently pinned at 2.6.6

The instanceu.py and Makefile required adjustment to be
aware of new file locations.