Move images around to match the directory structure in ka-stable.

Summary:
This should make it easier to keep images up-to-date between the two
repos.

Test Plan:
Once I have 'arc mail'-ed this off, I'll check that the images display
correctly for this revision in the two reading-pictograph exercises,
on sandcastle.

Reviewers: eater

Reviewed By: eater

Differential Revision: http://phabricator.khanacademy.org/D985

exercises/reading_pictographs_1.html

@@ -29,7 +29,7 @@
     <div class="vars">
         <var id="DATA">randRangeUnique( 1, 8, 5 )</var>
         <var id="BADGE">randFromArray([ "meteorite", "moon", "earth" ])</var>
-        <var id="FULL_IMAGE">"&lt;img src='" + Khan.urlBase + "images/" + BADGE + "-small.png'&gt;"</var>
+        <var id="FULL_IMAGE">"&lt;img src='" + Khan.urlBase + "images/badges/" + BADGE + "-small.png'&gt;"</var>
         <var id="VALUE_PER_IMG">1</var>
     </div>
 

exercises/reading_pictographs_2.html

@@ -29,8 +29,8 @@
     <div class="vars">
         <var id="DATA">randRangeUnique( 1, 8, 5 )</var>
         <var id="BADGE">randFromArray([ "meteorite", "moon", "earth" ])</var>
-        <var id="FULL_IMAGE">"&lt;img src='" + Khan.urlBase + "images/" + BADGE + "-small.png'&gt;"</var>
-        <var id="HALF_IMAGE">"&lt;div style=\"background-image:url('" + Khan.urlBase + "images/" + BADGE + "-small.png'); width:20px; height:40px;\"&gt;&nbsp;&lt;/div&gt;"</var>
+        <var id="FULL_IMAGE">"&lt;img src='" + Khan.urlBase + "images/badges/" + BADGE + "-small.png'&gt;"</var>
+        <var id="HALF_IMAGE">"&lt;div style=\"background-image:url('" + Khan.urlBase + "images/badges/" + BADGE + "-small.png'); width:20px; height:40px;\"&gt;&nbsp;&lt;/div&gt;"</var>
         <var id="VALUE_PER_IMG">randFromArray([ 2, 4 ])</var>
         <var id="HALF">VALUE_PER_IMG === 1 ? [ 0, 0, 0, 0, 0 ] : [ rand(2), rand(2), rand(2), rand(2), rand(2) ]</var>
     </div>