Output the name of the class explicitly in SpecReporter

This solves a problem when running through a DRb server such as spork of
outputing #<DRb::DRbUnknown:0x007ff87e126708> instead of the intended class name.

lib/minitest/reporters/spec_reporter.rb

@@ -32,7 +32,7 @@ def after_suites(suites, type)
       end
 
       def before_suite(suite)
-        puts suite
+        puts suite.name
       end
 
       def after_suite(suite)