Teach bdiff to support buffer objects manifest.add gives revlog.addrevision a buffer object, which may be cached and used for a second call in the same session (as mq does when pushing multiple patches). The other option would be to cast the buffer to str when caching it.

%% no changes
%% no changes
%% uncompressed contents in repo
this is a test
%% uncompress our working dir copy
this is a test
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
%% uncompress our new working dir copy
this is a test