Many updates/fixes to 2018/burton2

This is a big commit but it should complete this entry and 2018 unless I
have missed something.

The make test rule was fixed. A script was not +x.

Renamed freqcount -> freqcount.sh (for browser/display).

Renamed mkkeywords -> mkkeywords.sh (for browser/display).

Renamed runtest -> runtest.sh (for browser/display).

Renamed spotcheck -> spotcheck.sh (for browser/display).

Renamed spotdiff -> spotdiff.sh (for browser/display).

Made tac.man proper man format and renamed tac.1.

Added tokcount.sh - a script that the author included in the remarks but
not in a script.

The renaming of files should be okay including the manifest (it is
believed this is true anyway).

Add try.sh script.

The READ_ME.txt was deleted as it had been renamed to author-README.txt
but the former was never deleted. This file was typo/format checked.

Format/typo check README.md file.

2018/burton2/unob.sh

@@ -108,4 +108,4 @@ tern && /^:/	{ newline(); show($0); --tern; --n; next }
 { show($0) }
 '
 
-pp $* | $PROG -t | ./tokenfix | awk "$script" # sed 's/""//g'
+pp $* | $PROG -t | ./tokenfix.sh | awk "$script" # sed 's/""//g'