[conformal/btcutil] 97fea1: Add package documentation for base58 package.

[Dave Collins]

  Branch: refs/heads/master
  Home:   https://github.com/conformal/btcutil
  Commit: 97fea16721d2065733e50026d72d026bad479e6b
      
https://github.com/conformal/btcutil/commit/97fea16721d2065733e50026d72d026bad479e6b
  Author: Dave Collins <da...@conformal.com>
  Date:   2014-12-22 (Mon, 22 Dec 2014)

  Changed paths:
    M base58/README.md
    A base58/doc.go

  Log Message:
  -----------
  Add package documentation for base58 package.

This commit adds a doc.go file in the base58 package which provides
package documentation for godoc.