[conformal/btcwallet] ec8a5b: Refactor txToPairs into smaller functions

[Guilherme Salgado]

  Branch: refs/heads/master
  Home:   https://github.com/conformal/btcwallet
  Commit: ec8a5bc10ccc041c36843a3127ba7860aa9c7170
      
https://github.com/conformal/btcwallet/commit/ec8a5bc10ccc041c36843a3127ba7860aa9c7170
  Author: Guilherme Salgado <gsalg...@gmail.com>
  Date:   2014-10-28 (Tue, 28 Oct 2014)

  Changed paths:
    M createtx.go
    M createtx_test.go

  Log Message:
  -----------
  Refactor txToPairs into smaller functions

Also adds tests for those functions, and improve fee estimation.