Reintroduced zipped EPUB support after migration to the ReadiumSDK
renderer by wrapping globally-defined ReadiumSDK rendering functions.

Added necessary media-type metadata to package document structures,
needed for correctly rendering documents extracted from zipped EPUB
files.

Added missing error handler callback propagation within the epub-fetch
module.

Cleaned up old leftover stuff.

Updated the top-level Rakefile to launch a full build of everything.

Change-Id: I2cbb8b2b7bb3c1f8ca73d1945fad602d0117559e