Format 2013/dlowe, new script, rename others etc.

The demo.sh was renamed try.sh to be like the other entries.

The new script diff.sh runs some commands that I had previously added
(to demonstrate the entry) but which would be better in a script.

Renamed sflen.sh (for sparkline file length) to be slflen.sh (for
sparkline file length also).

Updated bugs.md - added more features that the author noted.

Format/typo check README.md file.

This should complete the review of 2013/dlowe.

2013/dlowe/slflen.sh

@@ -0,0 +1,19 @@
+#!/usr/bin/env bash
+#
+# 2013/dlowe/slflen.sh - show sparkline length of all files in the current
+# working directory
+#
+
+# make sure CC is set so that when we do make CC="$CC" it isn't empty. Doing it
+# this way allows us to have the user specify a different compiler in an easy
+# way.
+if [[ -z "$CC" ]]; then
+    CC="cc"
+fi
+
+make CC="$CC" all >/dev/null || exit 1
+
+ln -sf dlowe sparkl
+ls -1 *
+echo -n "sparkline length of above files: "
+wc -c ./* | awk '{print $1}' | xargs ./sparkl