Prevent scaling issues by improving efficiency of file writes

[adammcarth]

JTask isn't designed to scale anywhere close to a database in terms of performance, but it still should be reasonably fast (if not faster) in low to medium scale applications.

Currently, JTask methods save(), update(), chop() and destroy rewrite the entire file with the new version.

Surely there are better ways of doing this? A way to accurately write and delete characters from dynamic positions in a file should be at least looked into. I'll get around to posting some speed tests later showing the extent to which completely rewriting files effects scalability.