b=387156. r=gavin. changed sessionstorage to hold objects instead of strings

/**

 * Interface representing a simple storage system

 */

[scriptable, uuid(bbaf6210-aafe-11db-abbd-0800200c9a66)]

[scriptable, uuid(0787ac44-29b9-4889-b97f-13573aec6971)]

interface fuelISessionStorage : nsISupports

{

  /**

   * @param   aValue

   *          The value to assign to the item

   */

  void set(in AString aName, in AString aValue);

  void set(in AString aName, in nsIVariant aValue);

  /**

   * Gets the value of a storage item with the given name. Returns a

   * @returns value of the item or the given default value if no item

   *          exists with the given name.

   */

  AString get(in AString aName, in AString aDefaultValue);

  nsIVariant get(in AString aName, in nsIVariant aDefaultValue);

};