Add regression tests to distribution package

Add test target to the Makefile, and also automatically run tests
in the dist target. Current test results:

Run tests in /home/claudio/figlet/figlet
 _____       _                     _ _
|_   _|__ __| |_   _ _ ___ ____  _| | |_ ___
  | |/ -_|_-<  _| | '_/ -_|_-< || | |  _(_-<
  |_|\___/__/\__| |_| \___/__/\_,_|_|\__/__/

Run test 001: showfigfonts output... pass
Run test 002: text rendering in all fonts... pass
Run test 003: long text rendering... pass
Run test 004: left-to-right text... pass
Run test 005: right-to-left text... pass
Run test 006: flush-left justification... pass
Run test 007: flush-right justification... pass
Run test 008: center justification... pass
Run test 009: kerning mode... pass
Run test 010: full width mode... pass
Run test 011: overlap mode... pass
Run test 012: TLF font rendering... pass
Run test 013: kerning flush-left right-to-left mode... pass
Run test 014: kerning centered right-to-left mode (slant)... pass
Run test 015: full-width flush-right right-to-left mode... pass
Run test 016: overlap flush-right mode (big)... pass

 All tests passed.

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>

run-tests.sh

@@ -0,0 +1,61 @@
+#!/bin/sh
+
+TESTDIR=tests
+OUTPUT=`mktemp`
+LOGFILE=tests.log
+CMD=./figlet
+
+run_test() {
+	test_num=$1
+	test_dsc=$2
+	test_cmd=$3
+
+	echo >> $LOGFILE
+	echo -n "Run test $test_num: ${test_dsc}... " | tee -a $LOGFILE
+	echo >> $LOGFILE
+	eval "$test_cmd" > "$OUTPUT" 2>> $LOGFILE
+	cmp "$OUTPUT" "tests/res${test_num}.txt" >> $LOGFILE 2>&1
+	if [ $? -eq 0 ]; then
+		echo "pass" | tee -a $LOGFILE
+	else
+		echo "**fail**" | tee -a $LOGFILE
+		result=1
+		fail=`expr $fail + 1`
+	fi
+}
+
+result=0
+fail=0
+$CMD -v > $LOGFILE
+$CMD -f small "Test results" | tee -a $LOGFILE
+
+file="$TESTDIR/input.txt"
+cmd="cat $file|$CMD"
+
+run_test 001 "showfigfonts output" "./showfigfonts"
+run_test 002 "text rendering in all fonts" \
+  "for i in fonts/*.flf; do $cmd -f \$i; done"
+run_test 003 "long text rendering" "cat tests/longtext.txt|./figlet"
+run_test 004 "left-to-right text" "$cmd -L"
+run_test 005 "right-to-left text" "$cmd -R"
+run_test 006 "flush-left justification" "$cmd -l"
+run_test 007 "flush-right justification" "$cmd -r"
+run_test 008 "center justification" "$cmd -c"
+run_test 009 "kerning mode" "$cmd -k"
+run_test 010 "full width mode" "$cmd -W"
+run_test 011 "overlap mode" "$cmd -o"
+run_test 012 "TLF font rendering" "$cmd -f tests/emboss"
+run_test 013 "kerning flush-left right-to-left mode" "$cmd -klR"
+run_test 014 "kerning centered right-to-left mode (slant)" "$cmd -kcR -f slant"
+run_test 015 "full-width flush-right right-to-left mode" "$cmd -WrR"
+run_test 016 "overlap flush-right mode (big)" "$cmd -or -f big"
+
+rm -f "$OUTPUT"
+
+if [ $result -ne 0 ]; then
+	echo "\n $fail tests failed. See $LOGFILE for result details"
+else
+	echo "\n All tests passed."
+fi
+
+exit $result