fix problematic HTML caused by certain trailing backslashes

In cases that are **outside of a markdown code block**,
a markdown line with ending in a tailing "\" can generate
problematic HTML.

We certain trailing backslashes outside of a markdown code block
with "<br>" HTML elements, or in some cases eliminated the
need for a trailing backslash.

In a few cases some unnecessary trailing backslashes inside
of a markdown code block were removed.

The following markdown files were changed in this commit:

```
1990/dds/README.md
1990/jaw/README.md
1991/ant/README.md
1991/rince/README.md
1991/westley/README.md
1992/vern/README.md
1992/westley/README.md
1998/schweikh1/README.md
2004/anonymous/README.md
2005/sykes/README.md
2006/toledo2/README.md
2011/toledo/README.md
2012/endoh2/README.md
2012/tromp/README.md
2013/robison/README.md
2015/hou/README.md
2015/howe/README.md
2015/schweikhardt/README.md
2018/burton1/README.md
2018/burton2/README.md
2018/ferguson/README.md
2018/vokes/README.md
2020/ferguson1/README.md
```

Performed `make www` to test these changes.

2015/hou/README.md

@@ -116,7 +116,7 @@ Tested platforms:
 * Linux 3.18.7, Rasperberry Pi 2, clang 3.0-6.2, (works)
 * Linux 3.18.7, Rasperberry Pi 2, gcc 4.6.3, (works)
 * Mac OS X 10, x64, Apple LLVM version 6.1.0 (clang-602.0.53), (works)
-* Windows 8.1, x86, MSVC 2012 (works)\
+* Windows 8.1, x86, MSVC 2012 (works)
 * Windows 8.1, x64, MSVC 2012 (works)
 * Windows 8.1, x86, MinGW gcc 4.6.2 (fails, prints error message)
 * Windows 8.1, x86, MinGW gcc 4.6.2 with -msse2 -mfpmath=sse (works)

2015/hou/index.html

@@ -216,8 +216,7 @@ result. Error messages become garbled, though.</p></li>
 <li>Linux 3.18.7, Rasperberry Pi 2, clang 3.0-6.2, (works)</li>
 <li>Linux 3.18.7, Rasperberry Pi 2, gcc 4.6.3, (works)</li>
 <li>Mac OS X 10, x64, Apple LLVM version 6.1.0 (clang-602.0.53), (works)</li>
-<li>Windows 8.1, x86, MSVC 2012 (works)<br />
-</li>
+<li>Windows 8.1, x86, MSVC 2012 (works)</li>
 <li>Windows 8.1, x64, MSVC 2012 (works)</li>
 <li>Windows 8.1, x86, MinGW gcc 4.6.2 (fails, prints error message)</li>
 <li>Windows 8.1, x86, MinGW gcc 4.6.2 with -msse2 -mfpmath=sse (works)</li>