Make site fluid, add new homepage image

lms/static/sass/_course_about.scss

@@ -25,8 +25,9 @@
       @include clearfix;
       margin: 0 auto;
       max-width: 1200px;
+      min-width: 760px;
       position: relative;
-      width: grid-width(12);
+      width: 100%;
       z-index: 2;
 
 

lms/static/sass/_courses.scss

@@ -15,6 +15,7 @@
       height: 120px;
       margin: 0 auto;
       max-width: 1200px;
+      min-width: 760px;
       padding-top: 200px;
       position: relative;
       text-align: center;

lms/static/sass/_home.scss

@@ -19,7 +19,7 @@
       margin: 0 auto;
       padding: 200px 10px 0px;
       position: relative;
-      width: grid-width(12);
+      width: 100%;
     }
 
     .title {

lms/static/sass/_password_reset.scss

@@ -6,7 +6,7 @@
   @include box-shadow(0 5px 50px 0 rgba(0,0,0, 0.3));
   margin: 120px auto 0;
   padding: 0px 40px 40px;
-  width: grid-width(5);
+  width: flex-grid(5);
 
   header {
     margin-bottom: 30px;

lms/static/sass/base/_base.scss

@@ -83,7 +83,7 @@ a:link, a:visited {
   @include clearfix;
   margin: 0 auto 0;
   padding: 0px 10px;
-  width: grid-width(12);
+  max-width: grid-width(12);
 }
 
 span.edx {

lms/static/sass/shared/_footer.scss

@@ -15,7 +15,8 @@ footer {
     max-width: 1200px;
     margin: 0 auto;
     padding: 30px 10px 0;
-    width: grid-width(12);
+    max-width: grid-width(12);
+    min-width: 760px;
 
     .top {
       border-bottom: 1px solid rgb(200,200,200);

lms/static/sass/shared/_header.scss

@@ -13,7 +13,8 @@ header.global {
     margin: 0 auto;
     max-width: 1200px;
     padding: 14px 10px 0px;
-    width: grid-width(12);
+    max-width: grid-width(12);
+    min-width: 760px;
   }
 
   h1.logo {