webpack 4, gulp 4, @babel, node 8+ suggested dev env (#137)

* webpack 4, gulp 4, @bable, node 8+ suggested dev env

* using babel targets

* remove babel useBuiltIns, it was putting in unneeded polyfills

* boost target range for babel build and bump up the version major

.babelrc

@@ -1,9 +1,14 @@
 {
   "presets": [
-    "es2015",
-    "react"
+    [
+      "@babel/env", {
+        "targets": ">0.05%"
+      }
+    ],
+    "@babel/preset-react"
   ],
+
   "plugins": [
-    "transform-object-rest-spread"
+    "@babel/plugin-proposal-object-rest-spread"
   ]
 }

README.md

@@ -157,10 +157,11 @@ A full example is found in the `src/examples` directory.
 - run the `npm run test:watch` command run test in watch mode
 
 ### code test coverage
-- test coverage is done via istanbul
-- run the `npm run test:coverage` command to generate full coverage report (shown in terminal and as lcov report in coverage directory)
-- all code is run against coverage, not just the unit tested modules
-- test coverage improvement is currently a work in progress
+- ~~test coverage is done via istanbul~~
+- ~~run the `npm run test:coverage` command to generate full coverage report (shown in terminal and as lcov report in coverage directory)~~
+- ~~all code is run against coverage, not just the unit tested modules~~
+- ~~test coverage improvement is currently a work in progress~~
+- Note: As of v5.0.1 (the gulp / webpack upgrade) istanbul no longer works. We will replace with a new coverage tool soon.
 
 Current coverage sitting at v5.0.0:
 ```

docs/index.html

@@ -177,7 +177,7 @@
   <!--[if lt IE 8]>
     <p class="browsehappy">You are using an <strong>outdated</strong> browser. Please <a href="http://browsehappy.com/">upgrade your browser</a> to improve your experience.</p>
   <![endif]-->
-  <div class="lib-version">v5.0.1</div>
+  <div class="lib-version">v6.0.0</div>
 
   <div id="exList">
     <div class="title">Other Example Implementations</div>