[ErrorReport] List the installed plugins

[ErrorReportSpec] Update spec to include plugins list

[Hound] Clean up error report

[Hound] Remove explicit curly braces for hash in error report spec

[ErrorReport] Ensure plugins are sorted

Use the new CLAide::PluginsHelper method

lib/cocoapods/user_interface/error_report.rb

@@ -32,6 +32,12 @@ module Pod
 Ruby lib dir : #{RbConfig::CONFIG['libdir']}
 Repositories : #{repo_information.join("\n               ")}
 ```
+
+### Plugins
+
+```
+#{plugins_string}
+```
 #{markdown_podfile}
 ### Error
 
@@ -99,6 +105,19 @@ EOS
           "#{version} (#{build})"
         end
 
+        def installed_plugins
+          CLAide::Command::PluginsHelper.specifications.
+            reduce({}) { |hash, s| hash.tap { |h| h[s.name] = s.version.to_s } }
+        end
+
+        def plugins_string
+          plugins = installed_plugins
+          max_name_length = plugins.keys.map(&:length).max
+          plugins.map do |name, version|
+            "#{name.ljust(max_name_length)} : #{version}"
+          end.sort.join("\n")
+        end
+
         def repo_information
           SourcesManager.all.map do |source|
             next unless source.type == 'file system'

spec/unit/user_interface/error_report_spec.rb

@@ -40,6 +40,14 @@ Repositories : repo_1
                repo_2
 ```
 
+### Plugins
+
+```
+cocoapods         : #{Pod::VERSION}
+cocoapods-core    : #{Pod::VERSION}
+cocoapods-plugins : 1.2.3
+```
+
 ### Podfile
 
 ```ruby
@@ -78,6 +86,11 @@ EOS
         @report.stubs(:host_information).returns(':host_information')
         @report.stubs(:xcode_information).returns(':xcode_information')
         @report.stubs(:repo_information).returns(%w(repo_1 repo_2))
+        @report.stubs(:installed_plugins).returns({
+                                                    'cocoapods' => Pod::VERSION,
+                                                    'cocoapods-core' => Pod::VERSION,
+                                                    'cocoapods-plugins' => '1.2.3'
+                                                  })
         report = remove_color(@report.report(@exception))
         report.should == expected
       end