Update CI configuration

* Move CircleCI to the atom/ci script
* Use the bundled Node.js and stop forcing install of Node.js v6

Author: Arcanemagus

.travis.yml

@@ -1,32 +1,20 @@
 ### Project specific config ###
-
-# Installed for linting the project
-language: node_js
+language: generic
 
 matrix:
   include:
     - os: linux
       env: ATOM_CHANNEL=stable
-      node_js: "6"
 
     - os: linux
       env: ATOM_CHANNEL=beta
-      node_js: "6"
 
     - os: osx
       env: ATOM_CHANNEL=stable
-      node_js: "6"
-
-env:
-  global:
-    - ATOM_LINT_WITH_BUNDLED_NODE="false"
 
 ### Generic setup follows ###
 script: 'curl -s https://raw.githubusercontent.com/atom/ci/master/build-package.sh | sh'
 
-# Needed to disable the auto-install step running `npm install`
-install: true
-
 notifications:
   email:
     on_success: never

appveyor.yml

@@ -1,15 +1,9 @@
 ### Project specific config ###
 environment:
-  ATOM_LINT_WITH_BUNDLED_NODE: "false"
-
   matrix:
   - ATOM_CHANNEL: stable
   - ATOM_CHANNEL: beta
 
-install:
-  # Install Node.js to run any configured linters
-  - ps: Install-Product node 6
-
 ### Generic setup follows ###
 build_script:
   - ps: iex ((new-object net.webclient).DownloadString('https://raw.githubusercontent.com/atom/ci/master/build-package.ps1'))

circle.yml

@@ -1,13 +1,8 @@
 test:
   override:
-    - curl -s https://raw.githubusercontent.com/Arcanemagus/ci/atomlinter/build-package.sh | sh
+    - curl -s https://raw.githubusercontent.com/atom/ci/master/build-package.sh | sh
 
 dependencies:
   override:
+    # If nothing is put here, CircleCI will run `npm install` using the system Node.js
     - echo "Managed in the script"
-
-machine:
-  node:
-    version: 6
-  environment:
-    ATOM_LINT_WITH_BUNDLED_NODE: "false"