Fix BTC subunit

See: https://en.bitcoin.it/wiki/Satoshi
Update list of authors and changelog
Merge pull request #323 from ticean/btc-subunit

Fix BTC subunit
Show deprecation warning in comparisions
Update AUTHORS and CHANGELOG
Merge pull request #325 from joshhepworth/feature-comparision-deprecation

Show deprecation warning in comparisions
version bump to 6.0.0.pre5
Add bank to disable exchanges
Add option to disallow currency conversion

Prevents the possibility of erroneous currency conversion
Update README and CHANGELOG
Merge pull request #326 from ohthatjames/disallow_currency_conversion

Disallow currency conversion
Allow to inherits from Money

Signed-off-by: chatgris <jboyer@af83.com>
Update AUTHORS and CHANGELOG.md

Let's be a good oss citizen. :)

Signed-off-by: chatgris <jboyer@af83.com>
Rename set_upt_default to setup_defaults

Signed-off-by: chatgris <jboyer@af83.com>
Merge pull request #330 from chatgris/inheritance

Allow to inherits from Money
version bump to 6.0.0
Fixed typo in deprecation warning.
Merge pull request #334 from zubin/master

Fixed typo in deprecation warning.
Update AUTHORS
Fix spelling of deprecated