hamamatsu: Move some variable declarations
hamamatsu: Support VMS/VMU slides without a NoLayers key

@stevben found some VMS slides containing

    Creator=NZUtil

and no NoLayers key.  We don't actually use NoLayers for anything, and
the test for the existence of the key was vestigial (left by 7d0c9062).
Remove the test.
jp2k: Support OpenJPEG 2.1.0

OpenJPEG 2.0.1 would also work, except that it has a different signature
for opj_stream_set_user_data().  Given the current state of OpenJPEG 2.x
deployment, supporting 2.0.1 doesn't seem worth the extra configure check
and preprocessor macro.

Fixes #109.