Change read/write method to accept Reader/Writer interface instead implementation

[nfalco79]

Could you change the methods read/write to accept the interfaces Reader/Writer instead the bufferred implementation.
This is better for who handle ConfigParser with string instead directly from files and avoid flush every times also if we are using not buffered writer.

[ASzc]

Plain Readers don't offer the readLine method, which is core to the parser. I can add another overloaded method: public Ini read(Reader reader) that simply wraps the given Reader in a BufferedReader. However, it's not clear from your description if that'd work for your use case.

I can wrap a Writer in a BufferedWriter as well, but I'm also unclear if that'd work for you.