Check Internet connection; NOPEERS if peerCount <= 1

Download parity as parity[.exe].part and then rename

Remove nodeHealth$, use peerCount$

Change makeContract$ to makeContract

Update light.js dependency (now without precompiled lib/)

Refactor CLI

Explain examples better

The example with Ropsten seemed to be confusing.

Miscellaneous small fixes (fether-electron / parity-electron)

Previously, e.g. fetchParity(w, {parityChannel: "beta"}) would set
onProgress to be undefined, rather than the default () => {}