Address: Change discoverMeta to classifyVersion and add a general address validation example

docs/Address.md

@@ -51,6 +51,12 @@ belong to.
 The code to do these validations looks like this:
 
 ```javascript
+
+// validate an address
+if (Address.isValid(input){
+  ...
+}
+
 // validate that an input field is a valid testnet address
 if (Address.isValid(input, Networks.testnet){
   ...

lib/address.js

@@ -117,30 +117,30 @@ Address._transformHash = function(hash){
  * @returns {Object} An object with keys: network and type
  * @private
  */
-Address._discoverMeta = function(buffer){
+Address._classifyFromVersion = function(buffer){
-  var meta = {};
+  var version = {};
   switch(buffer[0]){ // the version byte
     case Networks.livenet.pubkeyhash:
-      meta.network = Networks.livenet;
+      version.network = Networks.livenet;
-      meta.type = Address.PayToPublicKeyHash;
+      version.type = Address.PayToPublicKeyHash;
       break;
 
     case Networks.livenet.scripthash:
-      meta.network = Networks.livenet;
+      version.network = Networks.livenet;
-      meta.type = Address.PayToScriptHash;
+      version.type = Address.PayToScriptHash;
       break;
 
     case Networks.testnet.pubkeyhash:
-      meta.network = Networks.testnet;
+      version.network = Networks.testnet;
-      meta.type = Address.PayToPublicKeyHash;
+      version.type = Address.PayToPublicKeyHash;
       break;
 
     case Networks.testnet.scripthash:
-      meta.network = Networks.testnet;
+      version.network = Networks.testnet;
-      meta.type = Address.PayToScriptHash;
+      version.type = Address.PayToScriptHash;
       break;
   }
-  return meta;
+  return version;
 };
 
 /**
@@ -162,19 +162,19 @@ Address._transformBuffer = function(buffer, network, type){
   }
 
   network = Networks.get(network);
-  var meta = Address._discoverMeta(buffer);
+  var bufferVersion = Address._classifyFromVersion(buffer);
 
-  if (!meta.network || (network && network !== meta.network)) {
+  if (!bufferVersion.network || (network && network !== bufferVersion.network)) {
     throw new TypeError('Address has mismatched network type.');
   }
 
-  if (!meta.type || ( type && type !== meta.type )) {
+  if (!bufferVersion.type || ( type && type !== bufferVersion.type )) {
     throw new TypeError('Address has mismatched type.');
   }
 
   info.hashBuffer = buffer.slice(1);
-  info.network = meta.network;
+  info.network = bufferVersion.network;
-  info.type = meta.type;
+  info.type = bufferVersion.type;
   return info;
 };