jpountz/lz4-java — pull request #16 by stevenschlansker (2013-07-03 20:53:00+00:00)
Title: Double close causes exception, which violates Closeable contract.

LZ4's block streams inherit Closeable. Closeable's contract specifies:
```java
/**
* Closes this stream and releases any system resources associated
* with it. If the stream is already closed then invoking this
* method has no effect.
*
* @throws IOException if an I/O error occurs
*/
public void close() throws IOException;
```

Show that double-close is broken in a way that violates the contract. Add a fix.