add localisable strings for plugin library

core/language/en-GB/ControlPanel.multids

@@ -52,11 +52,14 @@ Plugins/Disabled/Status: (disabled)
 Plugins/Empty/Hint: None
 Plugins/Enable/Caption: enable
 Plugins/Enable/Hint: Enable this plugin when reloading page
+Plugins/Install: install
 Plugins/Installed/Hint: Currently installed plugins:
 Plugins/Languages/Caption: Languages
 Plugins/Languages/Hint: Language pack plugins
+Plugins/OpenPluginLibrary: open plugin library
 Plugins/Plugins/Caption: Plugins
 Plugins/Plugins/Hint: Plugins
+Plugins/Reinstall: reinstall
 Plugins/Themes/Caption: Themes
 Plugins/Themes/Hint: Theme plugins
 Saving/Caption: Saving

core/language/en-GB/Misc.multids

@@ -25,6 +25,7 @@ InvalidFieldName: Illegal characters in field name "<$text text=<<fieldName>>/>"
 LazyLoadingWarning: <p>Loading external text from ''<$text text={{!!_canonical_uri}}/>''</p><p>If this message doesn't disappear you may be using a browser that doesn't support external text in this configuration. See http://tiddlywiki.com/#ExternalText</p>
 MissingTiddler/Hint: Missing tiddler "<$text text=<<currentTiddler>>/>" - click {{$:/core/images/edit-button}} to create
 OfficialPluginLibrary: Official ~TiddlyWiki Plugin Library
+OfficialPluginLibrary/Hint: The official ~TiddlyWiki plugin library at tiddlywiki.com. Plugins, themes and language packs are maintained by the core team.
 PluginReloadWarning: Please save {{$:/core/ui/Buttons/save-wiki}} and reload {{$:/core/ui/Buttons/refresh}} to allow changes to plugins to take effect
 RecentChanges/DateFormat: DDth MMM YYYY
 SystemTiddler/Tooltip: This is a system tiddler