fixes #610, incorrect help output

lib/src/compiler/compiler.dart

Index: lib/src/compiler/compiler.dart
diff --git a/lib/src/compiler/compiler.dart b/lib/src/compiler/compiler.dart
index 63ccc69ed73d9154af048cdae68ab36d50abed48..638553977a41e3c1ec04ed7edf198b3f95322d30 100644
--- a/lib/src/compiler/compiler.dart
+++ b/lib/src/compiler/compiler.dart
@@ -248,12 +248,12 @@ class CompilerOptions {
   static ArgParser addArguments(ArgParser parser) => parser
     ..addFlag('summarize', help: 'emit an API summary file', defaultsTo: true)
     ..addOption('summary-extension',
-        help: 'file extension for Dart summary files', defaultsTo: 'sum')
+        help: 'file extension for Dart summary files', defaultsTo: 'sum', hide: true)

[nweiz, 2016/08/12 20:30:57]

Long line.

[Jennifer Messerly, 2016/08/12 21:08:01]

Done.

     ..addFlag('source-map', help: 'emit source mapping', defaultsTo: true)
     ..addFlag('source-map-comment',
         help: 'adds a sourceMappingURL comment to the end of the JS,\n'
             'disable if using X-SourceMap header',
-        defaultsTo: true)
+        defaultsTo: true, hide: true)
     ..addOption('modules',
         help: 'module pattern to emit',
         allowed: ['es6', 'legacy', 'node'],
@@ -270,20 +270,20 @@ class CompilerOptions {
         help: 'emit Closure Compiler-friendly code (experimental)',
         defaultsTo: false)
     ..addFlag('destructure-named-params',
-        help: 'Destructure named parameters', defaultsTo: false)
+        help: 'Destructure named parameters', defaultsTo: false, hide: true)
     ..addFlag('unsafe-force-compile',
         help: 'Compile code even if it has errors. ಠ_ಠ\n'
             'This has undefined behavior!',
-        defaultsTo: false)
+        defaultsTo: false, hide: true)
     ..addFlag('hoist-instance-creation',
         help: 'Hoist the class type from generic instance creations',
-        defaultsTo: true)
+        defaultsTo: true, hide: true)
     ..addFlag('hoist-signature-types',
-        help: 'Hoist types from class signatures', defaultsTo: false)
+        help: 'Hoist types from class signatures', defaultsTo: false, hide: true)

[nweiz, 2016/08/12 20:30:57]

Long line.

[Jennifer Messerly, 2016/08/12 21:08:01]

Done.

     ..addFlag('name-type-tests',
-        help: 'Name types used in type tests', defaultsTo: true)
+        help: 'Name types used in type tests', defaultsTo: true, hide: true)
     ..addFlag('hoist-type-tests',
-        help: 'Hoist types used in type tests', defaultsTo: true)
+        help: 'Hoist types used in type tests', defaultsTo: true, hide: true)
     ..addFlag('unsafe-angular2-whitelist', defaultsTo: false, hide: true);
 }