Make scripts terminate with a non-zero error code upon failure.

packages/usb/apply-config.js

@@ -1,6 +1,8 @@
 #!/usr/bin/env node
 const uhk = require('./uhk');
 
+process.on('unhandledRejection', e => {throw e});
+
 (async function() {
     const device = uhk.getUhkDevice();
     uhk.applyConfig(device);

packages/usb/eeprom.js

@@ -2,6 +2,8 @@
 const uhk = require('./uhk');
 const device = uhk.getUhkDevice();
 
+process.on('unhandledRejection', e => {throw e});
+
 (async function() {
     const operationArg = process.argv[2];
     const operation = uhk.eepromOperations[operationArg];

packages/usb/write-user-config.js

@@ -3,6 +3,8 @@ const fs = require('fs');
 const program = require('commander');
 const uhk = require('./uhk');
 
+process.on('unhandledRejection', e => {throw e});
+
 (async function() {
     program
         .usage(`configPath`)