Money version 2.6.0

Enhancements

• Change the definition of the money_with_currency composite Postgres type from numeric(20,8) to numeric. This provides for a much wider precision and scale. It also means that retrieving Money.t data from the database will be returned with the same scale as when it was stored. Closes #67. Thanks to @doughsay.

• Relaxes the requirements for ex_cldr and ex_cldr_numbers

• Adds json encoding for Money.t for jason and poison