Merge branch 'release/0.2.48' into develop
PAKDF infrastructure.
WIP auth flow.
Minimal registration and login with new API.
Minor fixes and cleanup.
Don't allow oldblob login, instead show migration hint.
Remove blob backend selector.
Starting to work on blob update functionality.
We can no longer show the password on the Security page - we don't know it.
Re-login (using keys.crypt and keys.id) implementation.
Blob: Add patch submission, application and consolidation.
Blob: Unified encryption logic. Deprecate metadata.
PAKDF: Add purpose token to publicInfo.
PAKDF: Use Angular.js $http service.
Implement wallet unlock for Send tab.
Blob: Fix filter opcode and implement contacts updating.
Keychain: Add generic unlock mechanism.

We can use this flow for the long tail of transactions where it's not worth
coming up with custom UI.
Blob: Add username and auth_secret to registration process.
Register: Better error handling. Add spinner.
Fix security tab.