Display buffer number with small digits and use + for modified files

Hi,

Please, consider following modifications. First, small numbers for the buffer number instead of those circled ones. And with no limit to 20. In fact it's very easy to have far more than 20 buffers open at a Vim session, because each new buffer, even just a help window increments the counter.
Second, I've changed those strange character for modified files to plain old but very well recognized "+" sign. It's just more readable and compatible with a lot of vim plugins.

How do you like it?