fix more broken markdown links

We fix more markdown links in markdown files that refer to files
internally to the web site.

Added tmp tools to find and print various markdown links:

* `tmp/md-links.sh` - print all markdown links
* `tmp/md-token-links.sh` - print all markdown links that start with a **%%TOKEN%%**
* `tmp/md-local-links.sh` - print all markdown links to a local file
* `tmp/md-link-paths.sh` - print local file paths referenced in markdown links

Fixed a number of markdown formatting problems with `thanks-for-help.md`.
Fixed markdown links to files in `thanks-for-help.md`.  Improved
heading levels in `thanks-for-help.md`, and made entry sections consistent.

Changed all markdown links that end in "))" to end in a better way.

Explained in `markdown.md` why we are avoiding markdown links that
end in "))".

Ran `make www` to perform the above.

TODO: Fix stuff we broke by mistake doing the above.

TODO: Fix more broken markdown links.

2012/endoh2/README.md

@@ -34,7 +34,7 @@ and:
 ## Judges' remarks:
 
 A
-[pi](https://en.wikipedia.org/wiki/Pi)/[e](https://en.wikipedia.org/wiki/E_(mathematical_constant))
+[pi](https://en.wikipedia.org/wiki/Pi)/[e](https://en.wikipedia.org/wiki/E_(mathematical_constant))
 printing quasi-[quine](https://en.wikipedia.org/wiki/Quine_(computing) in [ASCII
 art](https://en.wikipedia.org/wiki/ASCII_art) with a compressed font in it; what
 else to wish for in this program? [Virtual
@@ -47,7 +47,7 @@ Yeah, "Again".  Sorry.  But I don't feel guilty or uncomfortable.
 
 This entry is based on 'over-used themes' such as self reproducing
 program and [pi](https://en.wikipedia.org/wiki/Pi) or
-[e](https://en.wikipedia.org/wiki/E_(mathematical_constant))) computation.  I
+[e](https://en.wikipedia.org/wiki/E_(mathematical_constant() computation.  I
 know you're tired of them.
 
 But have you ever seen them **all-in-one**?
@@ -65,18 +65,18 @@ This program generates a new program in the shape of the Greek letter
 
 One more thing...  When you give a command line argument `e` to the
 first program, the generated one will compute [Napier's
-constant](https://en.wikipedia.org/wiki/E_(mathematical_constant)))
+constant](https://en.wikipedia.org/wiki/E_(mathematical_constant))
 rather than pi.
 
 
 ### Obfuscation
 
 This program itself is in the shape of a
-[spigot](https://en.wikipedia.org/wiki/Tap_(valve)).  This is derived as an
+[spigot](https://en.wikipedia.org/wiki/Tap_(valve)).  This is derived as an
 analogy with [spigot algorithm](https://en.wikipedia.org/wiki/Spigot_algorithm)
 which infinitely computes the value of a mathematical constant such as
 [pi](https://en.wikipedia.org/wiki/Pi) or
-[e](https://en.wikipedia.org/wiki/E_(mathematical_constant)).
+[e](https://en.wikipedia.org/wiki/E_(mathematical_constant)).
 
 The two sets of programs, `314*.c` and `271*.c`, are almost the same
 except their shape and constant computational part.  I tailored the
@@ -85,7 +85,7 @@ tweaking the computational order and adding meaningless code fragments.
 
 On the other hand, to make it fit inside one screen (80 x 25), my program is
 shortened properly, more than it looks.  (As you may know,
-[quines](https://en.wikipedia.org/wiki/Quine_(computing)) need to make its
+[quines](https://en.wikipedia.org/wiki/Quine_(computing)) need to make its
 program size doubled.) For example, this program involves 3x5 bitmap font data
 of ten characters (`0` -- `9`), as just 20 bytes: `G1%xJ{;Q7wunmuGuu%uu`.  We
 can decode character `n` as `275*s[n+10] - 8*s[n] - 8`.  I solved the system of