Remove logback references from ImportProcess

If log4j is present in ImageJ1 and is found before
logback, then having explicit imports of logback
classes in key loci-plugins classes will prevent
Bio-Formats from working at all.

This commit follows the previous strategy of hiding
the hefty lifting in LogbackTools and just referencing
those methods safely from a ReflectedUniverse in
DebugTools.
Fix the scope of logback dependencies in Maven

The Maven build should now pass.
Remove log4j jars
Fix LogbackTools to correctly override logback's defaults