fix #750
wizard: ask for password earlier during restore
Rewrite accounts and transactions: store pubkeys instead of addresses in order to avoid unnecessary derivations.
add_keypairs: simplification
rm duplicate method getpubkey
get_master_public_key: always return xpub of main account
fixes for pending accounts
transaction: separate deserialize and update methods
make seed dialog a bit wider
fix: get_action
Add tests to the wallet.py module.

This increases test coverage a lot.
Merge branch 'clean-tests-wallet'

Merging after solving conflicts.