Release 4.2.0

• Merge pull request #308 from bigchaindb/add-type-defs (6aa5f01)
• fix: add type for TransactionOutput.condition (1779f6e)
• Merge branch 'add-type-defs' of github.com:bigchaindb/js-bigchaindb-driver into add-type-defs (44dfc8f)
• fix: makeoutput input type (d5fd300)
• fix: Crypto conditions parsers (71fe66c)
• fix: refine Crypoconditions parsers types (af90b97)
• fix: refine types definitions (b177ca0)
• fix: add type definitions (858acf2)
• fix: module exports (d26f667)
• fix: makeoutput input type (c98cc8e)
• fix: Crypto conditions parsers (2a104eb)
• fix: refine Crypoconditions parsers types (90a2cb2)
• fix: refine types definitions (84bd4ef)
• fix: add type definitions (5f6bef6)
• fix: module exports (cd5c529)
• Merge pull request #307 from bigchaindb/update-dependencies (7fe9040)
• Merge branches 'update-dependencies' and 'update-dependencies' of github.com:bigchaindb/js-bigchaindb-driver into update-dependencies (902885f)
• fix: run lint (abaa40b)
• fix: lint config (611624f)
• fix: update example (3d49a67)
• fix: update test constants (978585d)
• fix: minor transaction module improvements (43c541d)
• fix: update release-it config (272e6d6)
• fix: update tests to latest AVA API (736b2ad)
• fix: update delegateSignTransaction callback (dc7634c)
• fix: update travis config (42112ac)
• fix: improve request errors (656de69)
• fix: update polyfills path (597ac56)
• fix: regenerate doc (1b9bafa)
• fix: update webpack config (e3cca78)
• fix: update babel and lint config (23c3fa5)
• fix: update dependencies and test config (551180b)
• fix: run lint (86d02c2)
• fix: lint config (90466cf)
• fix: update example (cc3aa3f)
• fix: update test constants (f5cd60e)
• fix: minor transaction module improvements (317bdd4)
• fix: update release-it config (41ce117)
• fix: update tests to latest AVA API (ba87737)
• fix: update delegateSignTransaction callback (d5894de)
• fix: update travis config (3c76d3b)
• fix: improve request errors (1f27cd2)
• fix: update polyfills path (57a3e89)
• fix: regenerate doc (e76c622)
• fix: update webpack config (ad7763f)
• fix: update babel and lint config (b3909b0)
• fix: update dependencies and test config (f0df142)
• Merge pull request #304 from bigchaindb/delegated-signature (6dbafa8)
• fix: remove transaction from delegated signature callback (3447022)
• add example usage (a4d8ff5)
• update contact link (54ecf63)
• update tendermint version in docker compose (f5c2e92)
• test delegated signature (4b0d5c4)
• add delegateSignTransaction static method (b2e4ef5)