java.io.File.toURL() does not properly encode characters

```
As we use this method in a lot of places in our code we need to replace it with 
code that generates properly encoded URIs.

Example:

new File("/tmp/a+b").toURL() returns "file:/tmp/a+b". This is incorrect as it 
should be "file:/tmp/a%2Bb" instead.

```

Original issue reported on code.google.com by `indiapaleale@gmail.com` on 24 Nov 2010 at 7:50
