Replace bitcoin with dogecoin in Debian files. Based on commit
3c99a18a7d00d5f41870a7312ba06a22573e6424

- Primarily bitcoin Bitcoin and BITCOIN
- A few fixes (e.g. bitcoin.org -> dogecoin.com)
- Debian building not actually tested, I'm doing this to prep for RPMs
Renamed Debian contrib files to replace Bitcoin with Dogecoin.
Replaced remaining references to Bitcoin, with Dogecoin, in Debian contrib.
Merge pull request #410 from rnicoll/1.7-dev-debian

Replace Bitcoin references in Debian contrib