Bump component versions

The following changes were made:
	scripting-jython.version = 0.1.4 (latest org.scijava:scripting-jython)
	nar.version = 3.2.0 (latest com.github.maven-nar:nar-maven-plugin)
	jfreechart.version = 1.0.19 (latest org.jfree:jfreechart)
	miglayout.version = 3.7.4 (latest com.miglayout:miglayout)

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
enforcer: Remove now-obsolete special handling of jython-standalone

We just switched to a scripting-jython version that depends on
jython-shaded; This artifact no longer conflicts with JRuby's
dependencies.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>