Add runner to generate html documentation.

Implemented runner which translates each .txt
file located in doc/ to html by using markdown.

refs #4214

bin/createdoc.sh

@@ -0,0 +1,7 @@
+#!/bin/sh
+
+for filepath in `find ../doc -type f -name "*.txt"`; do
+    markdown $filepath > `dirname $filepath`/`basename $filepath .txt`.html
+done
+
+exit 0