WIP - squash 147 commits

This commit implements a new secure, scalable, hierarchical deterministic
wallet address manager.

The following is an overview of features:

- BIP0032 hierarchical deterministic keys
- BIP0043/BIP0044 multi-account hierarchy
- Strong focus on security:
  - Fully encrypted database including public information such as
    addresses as well as private information such as private keys and
    scripts needed to redeem pay-to-script-hash transactions
  - Hardened against memory scraping through the use of actively clearing
    private material from memory when locked
  - Different crypto keys used for public, private, and script data
  - Ability for different passphrases for public and private data
  - Scrypt-based key derivation
  - NaCl-based secretbox cryptography (XSalsa20 and Poly1305)
  - Multi-tier scalable key design to allow instant password changes
    regardless of the number of addresses stored
- Import WIF keys
- Import pay-to-script-hash scripts for things such as multi-signature
  transactions
- Ability to export a watching-only version which does not contain any
  private key material
- Programmatically detectable errors, including encapsulation of errors
  from packages it relies on
- Address synchronization capabilities

This commit only provides the implementation package.  It does not
include integration into to the existing wallet code base or conversion of
existing addresses.  That functionality will be provided by future
commits.
WIP since initial review - squash 18 commits
Allow injection of crypto keys into the manager.

Useful to test error conditions.

Also provide a new function that wraps snacl.GenerateCryptoKey(),
defined as a variable so that it can be replaced in tests.
Unexport the cryptoKey type.

The crypto key type unsed in the manager is not needed outside of the
package.  Also, rather than having the newCryptoKey func return the
specific cryptoKey type, make it return the EncryptorDecryptor interface.
This will allow it to be overridden with another type that implements the
interface from the tests.
IMPORT PATH MODIFICATION CHANGESET
----------------------------------

Please use this changeset as the first one on top of the conformal codebase.
Note that if there are new imports, they need to be changed as part of this
changeset. In general, use "git rebase" on github.com/conformal's version
and apply this changeset first.
Squash 24 changesets.

Implement voting pools deposit side.
Add restrictions to replace and create series

The minimum number of public keys is now three and the number of
required signatures must be less than the number of public keys
Fix teknico's code review comment
Add a couple new tests to DepositScriptAddress
Simplify some of our tests by using reflect.DeepEqual
Add HD Wallet integration (temporary and hacky!!!)

Add RPC/Websocket calls for:

getdepositscript
createseries
replaceseries
thawseries
Add more error codes, messages and error checking.
Added notifications for deposit scripts
Strengthen tests by checking the correct error code is returned
Fixed according to Nicola's review comments
Get rid of redundant tests for create/replace series

And make sure they test what they're supposed to
Lowercased error messages, cleared up comments, shortened some lines.
No functional changes.
pool_test.go reformatting
- uniformed all messages with actual value first, expected second
- clarified error messages
- made comments more readable
- shortened long lines

No functional changes.
Revised changes with Lars, should be more reasonable now. :-)
Oops. :-) Syntax errors fixed.