[epub32] updated deprecated text

Further to the call earlier, I've updated the google doc[1] to reflect the
comments I was hearing. In particular:

 

*	reading system support for deprecated features is dropped to "may";
*	I've emphasized the lack of use or support in the text and noted not
to spend time adding support;
*	also made a minor editorial clarification that the features are not
supported in "this specification" not the "current specification", which is
technically a different thing.

 

Please feel free to suggest any additional changes to the document.

 

[1]
https://docs.google.com/document/d/1pT_Osug3yPnLTfaMEUcW4N9-Mk8lUupdG6yb36x4
tWc/edit?usp=sharing

 

Matt