Updated Testnet and Parallel Networks information

- Rename "XRP Test Net" to "XRP Ledger Testnet"
- Add XRP Ledger Devnet to tooling
- Update "Parallel Networks" page to describe Testnet & Devnet,
  and fix typos.
- Add "Mainnet" as a name for the production XRP Ledger network (in
  context of testnets)

assets/js/test-net.js

@@ -1,39 +1,52 @@
-function rippleTestNetCredentials() {
+function rippleTestNetCredentials(url, altnet_name) {
 
-  var credentials = $('#your-credentials');
-  var address = $('#address');
-  var secret = $('#secret');
-  var balance = $('#balance');
-  var loader = $('#loader');
+  const credentials = $('#your-credentials')
+  const address = $('#address')
+  const secret = $('#secret')
+  const balance = $('#balance')
+  const loader = $('#loader')
 
   //reset the fields initially and for re-generation
-  credentials.hide();
-  address.html('');
-  secret.html('');
-  balance.html('');
-  loader.css('display', 'inline');
+  credentials.hide()
+  address.html('')
+  secret.html('')
+  balance.html('')
+  loader.css('display', 'inline')
 
 
   //call the alt-net and get key generations
   $.ajax({
-    url: "https://faucet.altnet.rippletest.net/accounts",
+    url: url,
     type: 'POST',
     dataType: 'json',
     success: function(data) {
       //hide the loader and show results
       loader.hide();
-      credentials.hide().html('<h2>Your Credentials</h2>').fadeIn('fast');
-      address.hide().html('<h3>Address</h3> ' + data.account.address).fadeIn('fast');
-      secret.hide().html('<h3>Secret</h3> ' + data.account.secret).fadeIn('fast');
-      balance.hide().html('<h3>Balance</h3> ' + Number(data.balance).toLocaleString('en') + ' XRP').fadeIn('fast');
+      credentials.hide().html('<h2>Your Credentials</h2>').fadeIn('fast')
+      address.hide().html('<h3>Address</h3> ' +
+        data.account.address).fadeIn('fast')
+      secret.hide().html('<h3>Secret</h3> ' +
+        data.account.secret).fadeIn('fast')
+      balance.hide().html('<h3>Balance</h3> ' +
+        Number(data.balance).toLocaleString('en') + ' XRP').fadeIn('fast')
     },
     error: function() {
       loader.hide();
-      alert("There was an error with the Ripple Test Net, please try again.");
+      alert("There was an error with the "+altnet_name+" faucet. Please try again.");
     }
-  });
+  })
 }
 
 $(document).ready(function() {
-  $('#generate-creds-button').click(rippleTestNetCredentials);
-});
+  function testnet_click(evt) {
+    rippleTestNetCredentials("https://faucet.altnet.rippletest.net/accounts",
+      "Testnet")
+  }
+  function devnet_click(evt) {
+    rippleTestNetCredentials("https://faucet.devnet.rippletest.net/accounts",
+      "Devnet")
+  }
+
+  $('#testnet-creds-button').click(testnet_click)
+  $('#devnet-creds-button').click(devnet_click)
+})