[conformal/btcdb] d22696: Add a new memory database backend named memdb.

[Dave Collins]

  Branch: refs/heads/master
  Home:   https://github.com/conformal/btcdb
  Commit: d2269684720afa0fa79f7b5f4c65e398304274c2
      
https://github.com/conformal/btcdb/commit/d2269684720afa0fa79f7b5f4c65e398304274c2
  Author: Dave Collins <da...@conformal.com>
  Date:   2013-11-08 (Fri, 08 Nov 2013)

  Changed paths:
    M common_test.go
    A memdb/doc.go
    A memdb/driver.go
    A memdb/memdb.go
    A memdb/memdb_test.go

  Log Message:
  -----------
  Add a new memory database backend named memdb.

This commit adds a new backend driver which conforms to the btcdb
interface to provide a memory only database.  This is primarily useful for
testing purposes as normal operations require a persistent block storage
mechanism.