Default to Ignoring the Script that Called Amber

[Miserlou]

I have a lot of things to template, so I use Amber in a script. Every time, Amber wants to replace the values found in that script which is currently telling amber to replace those values, so I have to be very careful not to ruin my script!

It'd be create that if amber could detect if, for instance, it is being called by /foo/bar/create_template.sh then /foo/bar/create_template.sh would be omitted from the list of files to be replaced.

Related to #47