Added printing empty lines after compilation

Adding printing an empty line after a compile iteration has finished
makes it easier to parse the output and look for errors.

rubberin

@@ -163,6 +163,7 @@ end
 # do an initial run.
 files = `rubber-info --deps #{infile}`.chomp.split
 compile(infile, mode)
+puts ""
 
 # Spawn a viewer based on the mode.
 viewer_pid = fork
@@ -196,6 +197,7 @@ dirs.each do |dir|
     puts "I: file #{ev.name} modified, compiling #{infile}..."
     compile(infile, mode)
     reload(infile, mode)
+    puts ""
   end
 end