Auto versioning build tool

[AlexLynd]

We're losing track of software versions across the USB Nugget, which will make it hard to figure out if we're dealing with new bugs as they're being reported by customers. The Nugget interface itself only displays a static "v1.0" graphic, while the web interface refers to v1.0.4 and its unclear if that's the web UI version or the actual USB Nugget software.

We should create a tool that lets us keep track of versions in a single file, and automatically replace instances of the version upon building.