PR fixes; remove all infura token references and setup travis to use encrypted env

variable; rest of the ethjson_rpc dependent tests extracted to integration_test

pkg/plugin/test_helpers/database.go

@@ -54,7 +54,7 @@ func SetupDBandBC() (*postgres.DB, core.BlockChain) {
 }
 
 func TearDown(db *postgres.DB) {
-	tx, err := db.Begin()
+	tx, err := db.Beginx()
 	Expect(err).NotTo(HaveOccurred())
 
 	_, err = tx.Exec(`DELETE FROM headers`)