Don't install node on CI

Update electron-builder to fix AppImage (fix #166)

Fix the symbol bug

Fix markup (fix gap between accounts in AccountsList)

Improvements to health status

AccountsList: add hint to account creation

Fix linux icon

Replace healthStore w/ withHealth HOC

* RPC methods$() are now called after the API is set
* Fix accountsInfo$() race condition (accountsList)
* Render component decorated with withHealth immediately (fix
"Connecting to node" not rendering)

Use new version of @parity/light.js