Couple of improvements for the tangle/ directory:
a) Start running tangle unit tests at build time again.
b) Option to print out test names as they run, just like in top-level.
Fix CI. Scenario size_of_shape_shifting_exclusive_container was
triggering undefined behavior in tangle/ and causing things to break in
some compilers but not others.
I'd been toying with this idea for some time now given how large the
repo had been growing. The final straw was noticing that people cloning
the repo were having to wait *5 minutes*! That's not good, particularly
for a project with 'tiny' in its description. After purging .traces/
clone time drops to 7 seconds in my tests.
Major issue: some commits refer to .traces/ but don't really change
anything there. That could get confusing :/
Minor issues:
a) I've linked inside commits on GitHub like a half-dozen times online
or over email. Those links are now liable to eventually break. (I seem
to recall GitHub keeps them around as long as they get used at least
once every 60 days, or something like that.)
b) Numbering of commits is messed up because some commits only had
changes to the .traces/ sub-directory.
Required fixing two levels of bugs:
a) The hack in tangle to drop initial comments a '%' directive..
b) ..was masking a bug where run_mu_scenario wasn't robust to initial
comments.
Mildly concerned that neither of the sub-issues have their own tests,
but I'm just removing hacks, and writing tests for that throwaway
function like run_mu_scenario seems pointless. Instead I've solved the
problem by disallowing comments before '%' directives.
I've also taken this opportunity to at least try to document the
'scenarios' and '%' directives at the first layer where they appear.
