Auto-update octant client

[wwitzel3]

@bryanl commented on Sat Sep 22 2018

The octant client should be able to check if it is outdated, and update itself to the current version.

[wwitzel3]

Thoughts about this:

• alert user there is a new version
• they can say yes/no
• download octant binary
• replace old one
• restart

[wwitzel3]

probably another issue for check for updates preference

[wwitzel3]

might not be able to do this on macOS due to non-signed binary

[wwitzel3]

related #2011

[lenriquez]

I can work in this one