Close the RandomAccessFile instance to prevent IO Exceptions.

large numbers of files being scanned would yield
Exception in thread "main" java.io.FileNotFoundException: <redacted> (Too many open files)
	at java.io.RandomAccessFile.open(Native Method)
	at java.io.RandomAccessFile.<init>(RandomAccessFile.java:241)
	at silly.metrics.KeywordCounter.recurse(KeywordCounter.java:222)
	at silly.metrics.KeywordCounter.recurse(KeywordCounter.java:218)
	at silly.metrics.KeywordCounter.recurse(KeywordCounter.java:218)

silly-metrics/src/main/java/silly/metrics/KeywordCounter.java

@@ -222,6 +222,7 @@ else if (file.getName().endsWith(".java")) {
             RandomAccessFile f = new RandomAccessFile(file, "r");
             byte[] contents = new byte[(int) f.length()];
             f.readFully(contents);
+            f.close();
             String content = new String(contents);
 
             char c;