Don't test Node 5 in CI

Node 5 is neither latest or LTS. This is not removing support for
Node 5, it's simpky removing it from day-to-day CI for faster builds.

.travis.yml

 language: node_js
 node_js:
   - "6"
-  - "5"
   - "4"
   - "0.12"
   - "0.10"

appveyor.yml

@@ -63,7 +63,7 @@
                .{ process { (
                   @( $BindingName,
                        ( ( $_, "binding.node" ) -join '_' ) ),
-                  @( ".\build\Release\binding.pdb", 
+                  @( ".\build\Release\binding.pdb",
                        ( ( $_, "binding.pdb" ) -join '_' ) )
                ) } } | % { Push-AppveyorArtifact $_[0] -FileName $_[1] }
 
@@ -112,7 +112,6 @@
       - nodejs_version: 0.10
       - nodejs_version: 0.12
       - nodejs_version: 4
-      - nodejs_version: 5
       - nodejs_version: 6
 
   install: