Get rid of the old print command

We’ll be introducing a help command to replace it
Add support for retrieving formatted text content from the fake dom

The idea is to convert HTML block elements into newlines, so that the
output is readable on a terminal.
Add a new "commands" filter
Add help command
Move command documentation into the core
Docs update
Merge pull request #437 from pmario/de-DE

de-DE added favicon and typo fixes
changed favicon, so flag colors are right now
Add first pass at a tag manager

As independently suggested by @Skeeve and @Spangenhelm
Whoops, retract change to defaulttiddlers
Use proper tag pills in the tag manager
More tag colours
Merge branch 'master' of https://github.com/Jermolene/TiddlyWiki5 into de-DE
help text tiddlers translated to de-DE