accessibility fixes and minor css changes.

- added aria-hidden = "true" to prevent icons to be read by screen readers
- moved code on pages into "page-header" for better consistency

Change-Id: I3f497b2707991f7f628892a05734eea183a0d01d
Signed-off-by: Michael Davis <michael.s.davis@ibm.com>
diff --git a/app/common/styles/layout/content.scss b/app/common/styles/layout/content.scss
index 5225284..ad5e74f 100644
--- a/app/common/styles/layout/content.scss
+++ b/app/common/styles/layout/content.scss
@@ -6,7 +6,7 @@
 .page-header {
   position: relative;
   border-bottom: 1px solid $lightbg__grey;
-  margin: 1.625em 0 1.2em 0;
+  margin: .5em 0 2.2em;
   padding-left: 0;
   .h4 {
     padding: .1em 0 0 0;
@@ -22,6 +22,10 @@
   @include mediaQuery(x-small){
     padding: 1rem 2rem;
   }
+  section.row,
+  .column.row.row, .row.row.columns{
+    margin-left: 0;
+  }
 }
 
 .content-header {