[FIX] Fixed some hidden classes problem, improved binary image field's styling

bzr revid: fme@openerp.com-20120612081812-5w6e2bmg0pl6ou12

addons/web/static/src/css/base.sass

@@ -1294,10 +1294,10 @@ $colour4: #8a89ba
     .oe_form_invisible
         display: none !important
     .oe_form_editable .oe_form_editable_hidden
-        display: none
+        display: none !important
     .oe_form_readonly
         .oe_form_readonly_hidden, .oe_form_field:empty
-            display: none
+            display: none !important
     .oe_form
         .oe_form_field_text
             width: 100%
@@ -1556,7 +1556,7 @@ $colour4: #8a89ba
                 top: 1px
                 padding: 3px 0 0 0
                 margin: 0 1px
-                @include opacity(0.7)
+                display: none
                 width: 99%
                 text-align: center
                 background: url(/web/static/src/img/form_sheetbg.png)
@@ -1566,7 +1566,7 @@ $colour4: #8a89ba
                 -ms-box-sizing: border-box
                 box-sizing: border-box
             &:hover .oe_form_field_image_controls
-                @include opacity(1)
+                display: block
     // }}}
     // FormView.separator {{{
     .oe_horizontal_border