Replace globwatcher by chokidar for native fs events

[jholster]

Advantages of using chokidar instead of globwatcher:

• chokidar uses native fs events instead of polling, taking less resources
• chokidar has excellent cross-platform support, globwatcher is buggy on Windows¹

¹) With globwatcher, I coudn't get parcelify to detect style changes at all on Windows 7 & Windows 10