Update package to 0.4.0, raised min dep of node.js to 4 due to

dependencies (proven through CI: cannot support 0.12.0 due to
the dependency chain), and add AppVeyor and Travis CI builds.
Updated the readme with build badges.

.appveyor.yml

@@ -0,0 +1,21 @@
+environment:
+  matrix:
+    - nodejs_version: "4"
+    - nodejs_version: "6"
+    - nodejs_version: "8"
+    - nodejs_version: "10"
+
+platform:
+  - x86
+  - x64
+
+install:
+  - ps: Install-Product node $env:nodejs_version
+  - npm install
+
+test_script:
+  - node --version
+  - npm --version
+  - npm test
+
+build: off

.jshintrc

@@ -1,13 +1,14 @@
 {
+  "boss": true,
   "curly": true,
   "eqeqeq": true,
+  "eqnull": true,
   "immed": true,
   "latedef": true,
   "newcap": true,
   "noarg": true,
+  "node": true,
   "sub": true,
   "undef": true,
-  "boss": true,
-  "eqnull": true,
-  "node": true
-}
+  "unused": true
+}

.travis.yml

@@ -0,0 +1,12 @@
+dist: xenial
+language: node_js
+
+node_js:
+  - "4"
+  - "6"
+  - "8"
+  - "lts/*"
+  - "node"
+
+before_script:
+  - npm install grunt-cli -g

LICENSE

@@ -0,0 +1,23 @@
+Copyright (c) 2012 Sindre Sorhus <sindresorhus@gmail.com>
+and contributors.
+
+Permission is hereby granted, free of charge, to any person
+obtaining a copy of this software and associated documentation
+files (the "Software"), to deal in the Software without
+restriction, including without limitation the rights to use,
+copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+OTHER DEALINGS IN THE SOFTWARE.

readme.md → README.md

@@ -1,12 +1,20 @@
-# grunt-shell-spawn
+# grunt-shell-spawn [![Build Status](https://travis-ci.org/jeking3/grunt-shell-spawn.svg?branch=master)](https://travis-ci.org/jeking3/grunt-shell-spawn) [![Build Status](https://travis-ci.org/jeking3/grunt-shell-spawn.svg?branch=master)](https://travis-ci.org/jeking3/grunt-shell-spawn)
 
-A fork of [sindresorhus][1]'s [grunt-shell][2] ***with support for background processes***.
-
-*(e.g.: start a `compass watch` in the background)*
+> A fork of [sindresorhus][1]'s [grunt-shell][2] ***with support for background processes***.
+> 
+> *(e.g.: start a `compass watch` in the background)*
+
+This plugin lets you:
 
------
+- Run processes synchronously or asynchronously.
+- Process stdout and stderr using functions.
+- Run a function when an asynchronous process ends that gets the exit code.
+- Kill an asynchronous process.
+
+### Requirements
 
-*This plugin requires grunt >= 0.4.x. For grunt 0.3.x, use version `0.1.3`.*
+- node.js 4.x or later
+- grunt 0.4 or later
 
 ### Install
 
@@ -98,6 +106,13 @@ The process will be killed with a SIGKILL.
 
 Please note that processes that are not killed will continue running even after grunt finishes, unless explicitly terminated using `:kill`. This means it is required to use `:kill` to clean up any processes you started, unless you want them to continue running in the background.
 
+## Release History
+
+ * 2019-01-29   v0.4.0   Added CI on Travis, AppVeyor; updated node.js engine dependency to >=4
+ * 2019-01-26   v0.3.12   Removed dependency on exec-sync to resolve security advisory
+ * 2015-01-07   v0.3.1   Fix the :kill task on UNIX and Windows
+ * 2013-04-06   v0.1.3   Last version with support for grunt 0.3.x
+
 ## License
 
 MIT License