Officially drop 1.3 (but it still works for now)

Also use more recent point releases of 1.4 and 1.5.

.travis.yml

@@ -1,8 +1,7 @@
 language: go
 go:
-- 1.3.3
-- 1.4.2
-- 1.5
+- 1.4.3
+- 1.5.1
 
 env:
   global:

README.md

@@ -18,7 +18,7 @@ Sarama is an MIT-licensed Go client library for Apache Kafka 0.8 (and later).
 
 Sarama provides a "2 releases + 2 months" compatibility guarantee: we support the two latest releases of Kafka
 and Go, and we provide a two month grace period for older releases. This means we currently officially
-support Go 1.3, 1.4, and 1.5, and Kafka 0.8.1 and 0.8.2.
+support Go 1.4 and 1.5, and Kafka 0.8.1 and 0.8.2.
 
 Sarama follows semantic versioning and provides API stability via the gopkg.in service.
 You can import a version with a guaranteed stable API via http://gopkg.in/Shopify/sarama.v1.