Added new standalone tool ntds_hashextract.rb

ntds_hashextract.rb
--------------------------

Is a standalone tool that extracts AD password hashes from an exported datable and a SYSTEM hive file.  

<pre>
Royces-MacBook-Pro:tools r3dy$ ./ntds_hashextract.rb 
USAGE: ./ntds_hashextract.rb [datatable] [SYSTEM HIVE]

Royces-MacBook-Pro:tools r3dy$ 
</pre>

As far as I can tell it works perfectly as long as the datatable was properly exported from NTDS.dit using Libesedb or equivalent tools.