Allow configurations for the dailybread.

This is a fix for this old version of dailybread. There is a better version of the dailybread on its way as part of a bigger refactoring. This fixes #23 on github.
Add currency symbol as a configurable as well.
Make taxman parameters extendable via the opts object
Merge pull request #24 from openspending/23-global-dailybread

Allow configurations for the dailybread.