[conformal/btcutil] 40ba1d: Add Amount.ToBTC convenience method.

[Josh Rickmar]

  Branch: refs/heads/master
  Home:   https://github.com/conformal/btcutil
  Commit: 40ba1daf690afbd356066e36c47ba0e4d071ddb0
      
https://github.com/conformal/btcutil/commit/40ba1daf690afbd356066e36c47ba0e4d071ddb0
  Author: Josh Rickmar <jr...@conformal.com>
  Date:   2015-01-02 (Fri, 02 Jan 2015)

  Changed paths:
    M amount.go
    M amount_test.go

  Log Message:
  -----------
  Add Amount.ToBTC convenience method.

Closes #26.