fixup! Use JSONInputStream to deserialize annotations
DEBUG
Prepare IndexItem to read JSON instead of serialized objects

When reading from a JSONInputStream, by necessity the fields' types are
not known before-hand, as e.g. a Class is serialized as its name (i.e.
as a String), and only when using the value in the proxy, it is apparent
what type it is actually expected to have.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
TO-UNDO
fixup! Use JSONInputStream to deserialize annotations
fixup! WIP: Initial stab at a JSONInputStream
fixup! DEBUG
fixup! TO-UNDO
fixup! Initial stab at a JSONOutputStream
fixup! DEBUG
fixup! Serialize annotations as JSON
fixup! TO-UNDO
fixup! Use JSONInputStream to deserialize annotations