Implement more wallet API endpoints

[mjovanc]

        /* Get the transactions starting at the given block, for 1000 blocks */
        .Get("/transactions/\\d+", router(&ApiDispatcher::getTransactionsFromHeight, walletMustBeOpen, viewWalletsAllowed))

        /* Get the transactions starting at the given block, and ending at the given block */
        .Get("/transactions/\\d+/\\d+", router(&ApiDispatcher::getTransactionsFromHeightToHeight, walletMustBeOpen, viewWalletsAllowed))

        /* Get the transactions starting at the given block, for 1000 blocks, belonging to the given address */
        .Get("/transactions/address/" + api_constants::addressRegex + "/\\d+", router(
                                                                                   &ApiDispatcher::getTransactionsFromHeightWithAddress, walletMustBeOpen, viewWalletsAllowed))

        /* Get the transaction private key for the given hash */
        .Get("/transactions/privatekey/" + api_constants::hashRegex, router(
                                                                         &ApiDispatcher::getTxPrivateKey, walletMustBeOpen, viewWalletsBanned))