The docs say this can happen for a directory if there's an I/O error.

Briar crashed when run in a device without bluetooth or without camera
such as an emulator.

Closes #514

Fixes #572, #578.

Will currently fail at runtime; requires a public key and a server onion.

Modified the project structure, removed module extension and went instead for a non-complete core dependency graph

Semi-encapsulated the core/api dependency graphs and created a proper structure to load eager singletons