Review StreamReader.skip logic

```
It may not be possible to provide a robust implementation of 
StreamReader.trySkip that works for all underlying InputStream types.

http://stackoverflow.com/a/14400985/24874

https://code.google.com/p/metadata-extractor/source/browse/Source/com/drew/lang/
StreamReader.java
```

Original issue reported on code.google.com by `drewnoakes` on 18 Jan 2013 at 5:05
