Update upstream dependencies to match googlesource

A few of the bower dependencies were outdated compared to those used by
googlesource. There was a noticable difference for the better in the
updated iron-overlay-behavior, in that the top menu scrolls with the
page when opened in the updated version, but not in the previous
version.

Change-Id: Ib7697f8a86132d667f180129d319b4f7d437ff3a

WORKSPACE

@@ -1055,8 +1055,8 @@ bower_archive(
 bower_archive(
     name = "iron-dropdown",
     package = "polymerelements/iron-dropdown",
-    sha1 = "63e3d669a09edaa31c4f05afc76b53b919ef0595",
-    version = "1.4.0",
+    sha1 = "ac96fe31cdf203a63426fa75131b43c98c0597d3",
+    version = "1.5.5",
 )
 
 bower_archive(
@@ -1069,15 +1069,15 @@ bower_archive(
 bower_archive(
     name = "iron-overlay-behavior",
     package = "polymerelements/iron-overlay-behavior",
-    sha1 = "83181085fda59446ce74fd0d5ca30c223f38ee4a",
-    version = "1.7.6",
+    sha1 = "74cda9d7bf98e7a5e5004bc7ebdb6d208d49e11e",
+    version = "2.0.0",
 )
 
 bower_archive(
     name = "iron-selector",
     package = "polymerelements/iron-selector",
-    sha1 = "c57235dfda7fbb987c20ad0e97aac70babf1a1bf",
-    version = "1.5.2",
+    sha1 = "e0ee46c28523bf17730318c3b481a8ed4331c3b2",
+    version = "2.0.0",
 )
 
 bower_archive(

lib/js/bower_archives.bzl

@@ -64,7 +64,7 @@ def load_bower_archives():
     sha1 = "f77eba3f6f6817f10bda33918bde8f963d450041")
   bower_archive(
     name = "iron-resizable-behavior",
-    package = "PolymerElements/iron-resizable-behavior",
+    package = "polymerelements/iron-resizable-behavior",
     version = "1.0.6",
     sha1 = "719c2a8a1a784f8aefcdeef41fcc2e5a03518d9e")
   bower_archive(

lib/js/bower_components.bzl

@@ -66,7 +66,6 @@ def define_bower_components():
     name = "iron-dropdown",
     license = "//lib:LICENSE-polymer",
     deps = [
-      ":iron-a11y-keys-behavior",
       ":iron-behaviors",
       ":iron-overlay-behavior",
       ":iron-resizable-behavior",