doc: add Error Handling article

Originally published on The Go Programming Language Blog, July 12, 2011.

http://blog.golang.org/2011/07/error-handling-and-go.html

Update #2547

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5475060
diff --git a/doc/progs/run b/doc/progs/run
index d8efe96..b4c63f8 100755
--- a/doc/progs/run
+++ b/doc/progs/run
@@ -31,6 +31,13 @@
 	eff_sequence.go
 "
 
+error_handling="
+	error.go
+	error2.go
+	error3.go
+	error4.go
+"
+
 go_tutorial="
 	cat.go 
 	cat_rot13.go 
@@ -52,6 +59,7 @@
 for i in \
 	$defer_panic_recover \
 	$effective_go \
+	$error_handling \
 	$go_tutorial \
 	go1.go \
 ; do