chore(ci): expand travis testing (#278)

* REMOVE webpack devDependency as we have multiple peerDep versions
* Add matrix testing against supported node & webpack versions
* Enable codecov.io reporting
* Add travis script for test and coverage
* Rename cov script to cover to take advantage of `postcover`
* Add postcover script for travis linting after testing
* Temporarily allows failures on `OSX` ( timeout on node4 )

README.md

@@ -1,4 +1,4 @@
-# babel-loader [![Build Status](https://travis-ci.org/babel/babel-loader.svg?branch=master)](https://travis-ci.org/babel/babel-loader)
+# babel-loader [![NPM Status](https://img.shields.io/npm/v/babel-loader.svg?style=flat)](https://www.npmjs.com/package/babel-loader) [![Build Status](https://travis-ci.org/babel/babel-loader.svg?branch=master)](https://travis-ci.org/babel/babel-loader)[![codecov](https://codecov.io/gh/babel/babel-loader/branch/master/graph/badge.svg)](https://codecov.io/gh/babel/babel-loader)
   > Babel is a compiler for writing next generation JavaScript.
 
   This package allows transpiling JavaScript files using [Babel](https://github.com/babel/babel) and [webpack](https://github.com/webpack/webpack).
@@ -25,7 +25,7 @@ __Note:__ If you're upgrading from babel 5 to babel 6, please take a look [at th
 module: {
   loaders: [
     {
-      test: /\.jsx?$/,
+      test: /\.js$/,
       exclude: /(node_modules|bower_components)/,
       loader: 'babel', // 'babel-loader' is also a valid name to reference
       query: {
@@ -46,7 +46,7 @@ You can pass options to the loader by writing them as a [query string](https://g
 module: {
   loaders: [
     {
-      test: /\.jsx?$/,
+      test: /\.js$/,
       exclude: /(node_modules|bower_components)/,
       loader: 'babel?presets[]=es2015'
     }
@@ -60,7 +60,7 @@ module: {
 module: {
   loaders: [
     {
-      test: /\.jsx?$/,
+      test: /\.js$/,
       exclude: /(node_modules|bower_components)/,
       loader: 'babel',
       query: {
@@ -75,7 +75,7 @@ module: {
 
   * `cacheDirectory`: Default `false`. When set, the given directory will be used to cache the results of the loader. Future webpack builds will attempt to read from the cache to avoid needing to run the potentially expensive Babel recompilation process on each run. If the value is blank (`loader: 'babel-loader?cacheDirectory'`) or `true` (`loader: babel-loader?cacheDirectory=true`) the loader will use the default cache directory in `node_modules/.cache/babel-loader` or fallback to the default OS temporary file directory if no `node_modules` folder could be found in any root directory.
 
-  * `cacheIdentifier`: Default is a string composed by the babel-core's version, the babel-loader's version and the contents of .babelrc file if it exists. This can set to a custom value to force cache busting if the identifier changes.
+  * `cacheIdentifier`: Default is a string composed by the babel-core's version, the babel-loader's version, the contents of .babelrc file if it exists and the value of the environment variable `BABEL_ENV` with a fallback to the `NODE_ENV` environment variable. This can be set to a custom value to force cache busting if the identifier changes.
 
 
   __Note:__ The `sourceMap` option is ignored, instead sourceMaps are automatically enabled when webpack is configured to use them (via the `devtool` config option).
@@ -105,14 +105,14 @@ module: {
 
   See the [docs](http://babeljs.io/docs/plugins/transform-runtime/) for more information.
 
-  **NOTE:** You must run `npm install babel-plugin-transform-runtime --save-dev` to include this in your project.
+  **NOTE:** You must run `npm install babel-plugin-transform-runtime --save-dev` to include this in your project and `babel-runtime` itelf as a dependency with `npm install babel-runtime --save`.
 
 ```javascript
 loaders: [
   // the 'transform-runtime' plugin tells babel to require the runtime
   // instead of inlining it.
   {
-    test: /\.jsx?$/,
+    test: /\.js$/,
     exclude: /(node_modules|bower_components)/,
     loader: 'babel',
     query: {
@@ -128,7 +128,7 @@ loaders: [
 If using cacheDirectory results in an error similar to the following:
 
 ```
-ERROR in ./frontend/src/main.jsx
+ERROR in ./frontend/src/main.js
 Module build failed: Error: ENOENT, open 'true/350c59cae6b7bce3bb58c8240147581bfdc9cccc.json.gzip'
  @ multi app
 ```
@@ -139,7 +139,7 @@ That means that most likely, you're not setting the options correctly, and you'r
 ```javascript
 loaders: [
   {
-    test: /\.jsx?$/,
+    test: /\.js$/,
     exclude: /(node_modules|bower_components)/,
     loader: 'babel?cacheDirectory=true'
   }
@@ -151,7 +151,7 @@ That's not the correct way of setting boolean values. You should do instead:
 ```javascript
 loaders: [
   {
-    test: /\.jsx?$/,
+    test: /\.js$/,
     exclude: /(node_modules|bower_components)/,
     loader: 'babel?cacheDirectory'
   }
@@ -165,7 +165,7 @@ loaders: [
   // the optional 'runtime' transformer tells babel to require the runtime
   // instead of inlining it.
   {
-    test: /\.jsx?$/,
+    test: /\.js$/,
     exclude: /(node_modules|bower_components)/,
     loader: 'babel',
     query: {