ScriptREPL: use service name from @Plugin metadata
ScriptREPL: use service name from @Plugin metadata

And fall back to the old behavior of synthesizing a name from the
class name when no name is specified in the @Plugin annotation.

Related discussion at:
https://gitter.im/scijava/scijava-common?at=5dcc215f92a84f79fe5da435

This commit is dedicated to Kyle Harrington.

scijava/scijava-common