Add support for the more copyright styles.

See issue #4.

Added support for the following copyright styles:

* Singular hyphen-separated: Copyright (C) 2010-2014
* Multiple comma-separated: Copyright (C) 2010,2011,2012
* Multiple mixed: Copyright (C) 2008,2010,2012-2014
* Multiple hyphen-separated: Copyright (C) 2008-2010,2012-2014

Although it still need work. It doesn't support multiple copyrights in
the same chunk of text.