New features added. Updated Node compatibility.

[cjbarth]

I've added several new features to this project and updated the libraries and the code to support newer version of Node.

Features added:

• templates from strings
• persisting version data between runs
• deleting old hashed files
• renaming target files instead of append hash
• include file name in hash

[cjbarth]

I would love to see your CI testing drop support for very old, unsupported, versions of Node.