1) Simplify the layout of the organize dialog content.

2) Use CSS to layout the thmbnail grid to the full dialog size.  Fixes ticker #848.
3) Separate css that can be themed into organize_theme.css.  This isolates the themed components into a separate file for easy of overriding by a theme.

modules/organize/css/organize.css

@@ -3,18 +3,18 @@
  */
 
 #g-organize {
-  height: auto;
   margin: 0 !important;
+  min-height: auto;
   padding: 0 !important;
   position: relative;
   width: 100%;
 }
 
 #g-organize-content-pane {
-  height: auto;
+  height: 100%;
   margin: 0 !important;
   padding: 0 !important;
-  position: relative;
+  position: absolute;
   width: 100%;
 }
 
@@ -23,11 +23,15 @@
  */
 
 #g-organize #g-organize-tree-container {
-  height: 100%;
-  overflow: auto;
   margin: 0;
+  min-height: 100%;
   padding: 0;
-  width: 19%;
+  position: relative;
+  width: 20%;
+}
+
+#g-organize #g-organize-tree-container h3 {
+  margin-bottom: 0.1em;
 }
 
 #g-organize-album-tree {
@@ -54,10 +58,10 @@
  */
 
 #g-organize #g-organize-detail {
-  height: 100%;
   margin: 0 !important;
-  overflow: hidden;
+  min-height: 100%;
   padding: 0 !important;
+  position: relative;
   width: 80%;
 }
 
@@ -71,21 +75,17 @@
   width: inherit;
 }
 
-#g-organize-microthumb-panel {
-  height: 100%;
-  margin: 0 !important;
-  position: relative;
-  padding: 0 !important;
-  width: 100%;
-}
-
 #g-organize-microthumb-grid {
-  height: 100%;
-  overflow: auto;
+  bottom: 1.8em;
+  left: 0;
+  margin: 0 !important;
+  overflow-x: hidden;
+  overflow-y: auto;
   padding: .4em !important;
-  position: relative;
+  position: absolute;
+  right: 0;
+  top: 1.6em;
 }
-
 .g-organize-microthumb-grid-cell {
   display: block;
   height: 100px;
@@ -112,8 +112,13 @@
  */
 
 #g-organize-controls {
+  bottom: 0;
+  height: 1.9em;
+  left: 0;
   margin: 0 !important;
-  padding: .2em .4em;
+  padding: .1em .4em;
+  position: absolute;
+  right: 0;
 }
 
 #g-organize-controls select {