Bug 1023661 - Add support for SeaMonkey to "places" modules

From a quick look at the places/ modules, it seems they are essentially wrappers to XPCOM backend so they should work on SeaMonkey. Tested with a very minimal add-on:

      let { search } = require("sdk/places/history");
      let { getFavicon } = require("sdk/places/favicon");
      let { Bookmark, save } = require("sdk/places/bookmarks");
      
      // Test history: search the most visited bug page on Bugzilla
      search(
        { url: "https://bugzilla.mozilla.org/*" },
        { sort: "visitCount" }
      ).on("end", function (results) {
          // Extract the favicon url on the Bugzilla page.
          getFavicon(results[0].url).then(function (url) {
              // Save the favicon in the bookmarks.
              let bookmark = Bookmark({ title: results[0].title + " - Favicon",
                                        url: url });
              let emitter = save(bookmark);
          });
      });