Travis testing gcc versions

gcc-4.5 has package dependency problems
Add gcc-4.9
diff --git a/.travis.yml b/.travis.yml
index 643ad73..3213e8b 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -16,10 +16,6 @@
       sudo: required
       dist: xenial
     - os: linux
-      env: SWIGLANG= GCC=4.5
-      sudo: required
-      dist: xenial
-    - os: linux
       env: SWIGLANG= GCC=4.6
       sudo: required
       dist: xenial
@@ -32,6 +28,10 @@
       sudo: required
       dist: xenial
     - os: linux
+      env: SWIGLANG= GCC=4.9
+      sudo: required
+      dist: xenial
+    - os: linux
       env: SWIGLANG= GCC=6
       sudo: required
       dist: xenial