Allow for custom object-to-string conversions

Some users would like to use formatted output methods like:

scribe.put("Here is my class: %t")

But have that call a custom class-to-inline-string method they define.

This release allows that.

Add an inline method to your class, which will be used instead of the default scribe.inline.
You can implement the custom inline method using scribe.format if you wish.