Remove unneccesary(about old Firefox) and unused codes #48

* Cleanup component.js & tombfix.js
* component.js: Remove ICache, ExtensionManager, CacheService, AppShellService, CookieService, PasswordManager, WindowWatcher, FaviconService,  StyleSheetService, FuelApplication
* component.js: Remove DocumentEncoder
* component.js: Remove findCacheFile(), convertFromUnplaceableHTML(),  convertFromByteArray(), registerSheet(), unregisterSheet()
* tombfix.js: IOService, ExtensionManager
* tombfix.js: getContents()
* utility.js: convertToXULElement()