Add FLV and WEBM formats.

Patch by Daimrod <daimrod@gmail.com>. Change too small for copyright.
* lisp/emms-source-file.el: Add customization parameters.

Patch by Daimrod <daimrod@gmail.com>. Change too small for copyright
papers.
Add thing-at-point to interactive input.

Patch by Daimrod <daimrod@gmail.com>. Change too small for copyright
papers.