[gnome-directory-thumbnailer] docs: Add a note about uninstallation to the README

[Philip Withnall <pwithnall src gnome org>]

commit 625629693f9cf037bfba3fbc83dc31fdace67e98
Author: Philip Withnall <philip withnall collabora co uk>
Date:   Sun Jan 25 09:51:59 2015 +0000

    docs: Add a note about uninstallation to the README
    
    If you uninstall, you should clear your thumbnail cache, or you will
    retain stale directory thumbnails.

 README |   10 ++++++++++
 1 files changed, 10 insertions(+), 0 deletions(-)
---
diff --git a/README b/README
index cfdb357..2f50644 100644
--- a/README
+++ b/README
@@ -15,6 +15,16 @@ Specifying the maximum thumbnail dimensions:
  $ gnome-directory-thumbnailer dir out.png -s 200
 This allows the maximum height and width to be specified (in pixels).
 
+Uninstallation
+--------------
+
+If you uninstall gnome-directory-thumbnailer, some of your directories may
+retain their generated thumbnails. If this is the case, delete directories:
+ ~/.cache/thumbnails
+ ~/.thumbnails
+to clear the generated directory thumbnails. Other thumbnails will then be
+regenerated on demand.
+
 Dependencies
 ============