support -h and --help standard options

bin/php-parse

@@ -101,6 +101,7 @@ Operations is a list of the following options (--dump by default):
         --var-dump          var_dump() nodes (for exact structure)
     -N, --resolve-names     Resolve names using NodeVisitor\NameResolver
     -c, --with-column-info  Show column-numbers for errors (if available)
+    -h, --help              Display this page
 
 Example:
     php-parse -d -p -N -d file.php
@@ -150,6 +151,10 @@ function parseArgs($args) {
             case '-c';
                 $attributes['with-column-info'] = true;
                 break;
+            case '--help':
+            case '-h';
+                showHelp('');
+                break;
             case '--':
                 $parseOptions = false;
                 break;