Consolidate options, prefs and config logic

[hinerm]

Currently, we have a package org.scijava.options with an OptionsService, as well as a separate net.imagej.config package with a ConfigFileParameters class for working with the ImageJ.cfg launcher file. We also have org.scijava.util.Prefs for managing persistence of key/value string pairs.

We should strongly consider consolidation of all these, eliminating any redundant concepts.

Migrated-From: http://trac.imagej.net/ticket/1451

[hinerm]

For after https://github.com/scijava/scijava-common/issues/96

[ctrueden]

See also https://github.com/scijava/scijava-common/pull/102