Updates combined Register, Login, and Password Reset views as per new design

* Reorders form fields, and updates labels, placeholders, and tip text
* Increases clickable area for links and labels.
* Removes "*" markers from required fields, and instead adds
  "(optional)" labels to visible optional fields.
* Updates font colors and sizes, and removes box shadows
* Adds custom drop-down styles
* Improves responsive design scaling for small screens
* Make Terms of Service and Honor Code open in new window to avoid losing form
  field values.

common/test/acceptance/pages/lms/login_and_register.py

@@ -220,7 +220,7 @@ class CombinedLoginAndRegisterPage(PageObject):
         if favorite_movie:
             self.q(css="#register-favorite_movie").fill(favorite_movie)
         if terms_of_service:
-            self.q(css="#register-honor_code").click()
+            self.q(css="label[for='register-honor_code']").click()
 
         # Submit it
         self.q(css=".register-button").click()

common/test/acceptance/tests/lms/test_lms.py

@@ -341,7 +341,7 @@ class RegisterFromCombinedPageTest(UniqueCourseTest):
 
         # Verify that the expected errors are displayed.
         errors = self.register_page.wait_for_errors()
-        self.assertIn(u'Please enter your Public username.', errors)
+        self.assertIn(u'Please enter your Public Username.', errors)
         self.assertIn(
             u'You must agree to the édX Terms of Service and Honor Code',
             errors