Upend the CaPriCon rendering pipeline, to allow for multiple output backends (for now, HTML and LaTeX)

Correct the behavior `type_of` function, causing it to fail on ill-typed terms instead of falsely succeeding

It was useful for debugging, though...

Rename the WiQEE.js executable into the more appropriate capricon-engine.js, since the main UI logic was moved to a dedicated library

Previously, the deepest holes were evaluated first, even when they
were syntactically positioned after some previous ones at a shallower
level.

Making the Folds into Traversals had the nice effect of forcing a
single-pass implementation of what was previously done in two stages,
causing the unintuitive evaluation order. Always trust your
Applicative functors, they won't betray you.

Output quoted characters as-is when generating Markdown from CaPriCon, to preserve the correct newline count

Annotate matching braces with text spans when generating CaPriCon paragraphs, to allow better syntax highlighting to take place

The old "{@ ... @}" syntax was a bit clunky, so I looked for a way to
make it more like the Lisp backquotes. That meant re-using the '}'
keyword for closing both quotes, and unquotes.

Since that meant introducing additional state into the interpreter, I
took it as an opportunity to put that information to good use, and
actually start discriminating between "constant" quotes and "exec"
quotes. Indeed, the ",{ ... } exec" pattern seemed to be common enough
that it deserved its own concept. Enter "${ ... }", and the notion of
"exec step".

This new distinction will also allow some rudimentary levels of
"compilation" to be offered to the users, by means of a function that
turns every "verb step" into the "exec step" that corresponds to that
verb's value at the time of linking. It's quite simple, but if it
could eliminate verb lookups from commonly-used functions, it could be
a nice easy performance win.

Add support for writing custom examples after CaPriCon code blocks, to make the resulting pages more easily explorable

Start defining two new builtins, 'showExpr' and 'showSyntax', to help when debugging the behaviour of macros

Update the repository URLs in the Curly documentation; update the install script to allow installing Bash completions in a standard location

Integrate the 'bashcomps.shl' library into the Curly package, so that unprivileged users can still benefit from great completions

Correct a small parser bug that caused some interactive commands to need two newlines instead of one