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/spotdiff.sh

@@ -0,0 +1,9 @@
+#!/usr/bin/env bash
+
+# filename is 17
+# 1=cl 2=cw 3=cc 4=ci 5=ts 6=kw 7=kws
+# 9    10   11   12   13   14   15
+awk '{
+	printf "cl %d cw %d cc %d ci %d ts %d kw %d ks %d %s %s\n",
+		$9-$1, $10-$2, $11-$3, $12-$4, $13-$5, $14-$6, $15-$7, $17, $18
+}'