This commit corrects various things found by the static checkers
(comments, unkeyed fields, return after some if/else).
Add generated files and legacy files to the whitelist to be ignored.
Catch .travis.yml up with btcd so goclean can be run.
This changes the wallet.Open function signature to remove the database
namespace parameters. This is done so that the wallet package itself
is responsible for the location and opening of these namespaces from
the database, rather than requiring the caller to open these ahead of
time.
A new wallet.Create function has also been added. This function
initializes a new wallet in an empty database, using the same
namespaces as wallet.Open will eventually use. This relieves the
caller from needing to manage wallet database namespaces explicitly.
Fixes#397.
