A store for binary tiddlers, layered above other stores.
It's purpose to avoid the unnecessary processing of the text
attribute when not neeed. This could save greatly on processing time
and cost.
experimental
See: http://cdent.tiddlyspace.com/ShuntedBinaryStore
When a tiddler is PUT we know if it is binary. If it is we can store
the text somewhere efficiently and then write a normal tiddler for the
metadata of that tiddler.
When a tiddler is GET we can get the metadata from the normal
tiddler and then get the text from the efficient place, only if
needed. We can manage the text in a subclass which treats the Tiddler
text attribute as a property.
In our first experiments we will use two layered text stores.