New ncdu, ncdc + btrfssize + misc changes

dat/dump-btrfssize

@@ -0,0 +1,40 @@
+=pod
+
+I<2016-08-16> - btrfs-size.pl is a quick little script to provide an overview
+of the disk space used by btrfs subvolumes. It's comparable to
+L<btrfs-size.sh|https://poisonpacket.wordpress.com/2015/05/26/btrfs-snapshot-size-disk-usage/>,
+but is somewhat faster and has a few options to sort the output.
+
+Honestly, it's still hard to draw any conclusions from the sizes provided by
+btrfs, but sadly, L<ncdu|https://dev.yorhel.nl/ncdu> is useless for
+snapshot-heavy filesystems.
+
+Only tested with btrfs-progs v4.4.1.
+
+B<Download:> L<btrfs-size.pl|https://p.blicky.net/FNPXpbwMXfTI.txt>
+(L<syntax-highligted version|https://p.blicky.net/FNPXpbwMXfTI>).
+
+
+=head2 Usage
+
+  btrfs-size.pl --help [-nser] <path>
+    -n  Order by path name
+    -s  Order by (total) subvolume size
+    -e  Order by exclusive subvolume size
+    -r  Reverse order
+
+
+=head2 Example output
+
+  # btrfs-size.pl /data
+  gfbf007/cur                               46.32 GiB   16.00 KiB
+  gfbf007/snap/2016-08-14.08                46.32 GiB  428.00 KiB
+  gfbf007/snap/2016-08-15.03                46.32 GiB  428.00 KiB
+  gfbf007/snap/2016-08-16.03                46.32 GiB   16.00 KiB
+  ggit011/cur                               23.92 MiB   16.00 KiB
+  ggit011/snap/2016-08-14.08                23.90 MiB  300.00 KiB
+  ggit011/snap/2016-08-15.08                23.92 MiB   16.00 KiB
+  gman015/cur                                3.74 GiB   16.00 KiB
+  gman015/snap/2016-08-14.08                 3.74 GiB  112.00 KiB
+  gman015/snap/2016-08-15.02                 3.74 GiB   96.00 KiB
+  gman015/snap/2016-08-16.02                 3.74 GiB   16.00 KiB