added studio logo to log in and sign up pages

cms/static/sass/_login.scss

@@ -1,7 +1,15 @@
+.edx-studio-logo-large {
+	display: block;
+	width: 224px;
+	height: 45px;
+	margin: 100px auto 30px;
+	background: url(../img/edx-studio-large.png) no-repeat;
+}
+
 .sign-up-box,
 .log-in-box {
 	width: 500px;
-	margin: 100px auto;
+	margin: auto;
 	border-radius: 3px;
 
 	header {

cms/templates/login.html

@@ -5,9 +5,11 @@
 
 <%block name="content">
 
+  <div class="edx-studio-logo-large"></div>
+
   <article class="log-in-box">
     <header>
-      <h1>Log in to edX</h1>
+      <h1>Log in to edX studio</h1>
     </header>
     <form class="log-in-form" id="login_form" action="login_post" method="post">
       <div class="row">

cms/templates/signup.html

@@ -3,9 +3,12 @@
 <%block name="bodyclass">no-header</%block>
 
 <%block name="content">
+
+<div class="edx-studio-logo-large"></div>
+
 <article class="sign-up-box">
   <header>
-    <h1>Register for edX Labs</h1>
+    <h1>Register for edX studio</h1>
   </header>
   <form id="register_form" method="post">
     <div id="register_error" name="register_error"></div>