Much cleanup to better match lesson text

lcthw/.gitignore

@@ -1 +1,2 @@
 ex1
+ex3

lcthw/Makefile

@@ -1,9 +1,10 @@
 CFLAGS ?= -Wall -g
 
-all: ex1
+all: ex1 ex3
 
 clean:
-	rm -f ex1
+	rm -f ex1 ex3
 
 test:
 	./ex1
+	./ex3

lcthw/ex2/.gitignore

@@ -1 +0,0 @@
-ex1

lcthw/ex2/ex1.c

@@ -1,12 +0,0 @@
-#include <stdio.h>
-
-/* This is a comment. */
-int main(int argc, char *argv[])
-{
-	int distance = 100;
-
-	// this is also a comment
-	printf("You are %d miles away.\n", distance);
-
-	return 0;
-}

lcthw/ex3/.gitignore

@@ -1 +0,0 @@
-ex3