MongoInfo got moved...
Make ConnInfo a public type.
ConnInfo.Check() -> ConnInfo.Validate().
dumper -> db.Dumper.
Move non-exported stuff out of export_test.go.
Move the legacy test stuff back into its own file.
Clarify that the db package should not expose implementation details.
var -> const.
Close the file if we get an error from the Stat() call.
Clarify why create() returns an open file instead of a filename.
Move the "testing helpers" back into export_test.go.
Add a backups abstraction.