report [#30814] Absolute Shape Keys not working in 2.6

This report points out thet absolute shape keys are unusable.

The problem is there was no way to adjust the play time of a shape key (all absolte shape keys would start at frame zero with no way to change the speed).

Added an 'eval_time' property to the key block that works like the curve path evaluation time, so the time in the keyblock can be controlled.

release/scripts/startup/bl_ui/properties_data_mesh.py

@@ -259,8 +259,9 @@ class DATA_PT_shape_keys(MeshButtonsPanel, Panel):
                     col.prop_search(kb, "relative_key", key, "key_blocks", text="")
 
             else:
-                row = layout.row()
+                row = layout.column()
                 row.active = enable_edit_value
+                row.prop(key, "eval_time")
                 row.prop(key, "slurph")