* Problem: we have unused and outdated fixtures
Solution: clean up fixtures and tests accordingly
* Problem: there are still unused fixtures
Solution: remove Merlin keys
* Problem: There are unnecessary markers
Solution: remove the tendermint marker for tests
* Problem: Source files contain no license info
Solution: Add comments with SPDX license info to source files
* Python 3 files don't need # -*- coding: utf-8 -*-
* Problem: Stateful validation doesn't raise double spend exception
Solution: Transaction.validate should raise exception DoubleSpend if the given
transaction is already a part of the database
* Problem: Double spend exception message not accurate
Solution: The exception message should state that the double spend is because of
spending the same input more than once in the transaction
* Problem: BigchainDB config has stale/deprecated parameters
- Remove `keyring` and `keypair` from config
- Update tests
- Add `tendermint` config
* Fix flake8
* Update some naming conventions and redundant changes
* Remove redundant routine `fast_query`
* Remove deprecated parameters and descriptions
* remove some more unwanted code
* Problem: Two flake8 errors made Travis fail
Solution: Fix the two flake8 errors
* Address comments
- Remove reference of nodes_except_me and me_private and me
as attributes of BigchainDB instances
- Update and re-add test(s)
- Do not introduce `tendermint` in configuration instead handle that
in a separate PR along with docs
* Address comments
- Remove tests that are already covered with 2.0
- Remove tests that are no longer relevant
- Add TODO for more cleanup
* Remove tendermint config from configure command
* implement output.condition.details marshalling and remove signature field
* rename outputs[].condition.details.subfulfillments to subconditions
* simpler threshold depth overlow handling
* pass public_key as kwarg
* change ccv1 condition uri in docs
* import base58 at top in test_transaction
* Remove asset.validate_asset and move its validation checks to other areas
* Move Asset.get_asset_id to Transaction
* Remove Asset and AssetLink models
* Add test against creating TRANSFER transactions with bad asset
* Allow AssetLinks to be used in place of Assets in the Transaction Model and enforce `Transaction.transfer()` to only take an AssetLink
* Remove AssetLink's inheritance from Asset
* Remove id from the Asset model
* Fix get_txids_by_asset_id query for rethinkdb after removing asset's uuid
Because `CREATE` transactions don't have an asset that contains an id
anymore, one way to find all the transactions related to an asset is to
query the database twice: once for the `CREATE` transaction and another
for the `TRANSFER` transactions.
* Add TODO notice for vote test utils to be fixtures
* Update asset model documentation to reflect usage of transaction id
* Fix outdated asset description in transaction schema
