Update dependencies, apply scalafmt, and resolve warnings

[mliarakos]

• Update to latest SBT 1.3
  • I'm not familiar with SBT plugins, so I didn't know if updating more would break something
• Updated Scala and dependencies to latest compatible with Scala.js 1.0.1
  • I can update Scala.js too if you are fine with the compatibility break
• Ported and applied akka scalafmt settings
  • I figured the akka settings were the best baseline, but I can change/customize
• Resolved compiler and style warnings
• Deprecated getMillisDuration and getNanosDuration since they belong to an Akka helper
  • I'm also wokring on an Akka.js PR that will re-introduce them there

[andreaTP]

I'm not familiar with SBT plugins, so I didn't know if updating more would break something

There are scripted tests for the sbt plugin: https://github.com/akka-js/shocon/blob/master/travis/testSbtPlugin.sh

I can update Scala.js too if you are fine with the compatibility break

Totally fine if this is the direction the community is taking!

I figured the akka settings were the best baseline, but I can change/customize

the automatic formatting in this repo have always been broken ... I'm happy with anything that is automated

Overall thanks a lot!

@mliarakos would you consider stepping up as a maintainer in the akka-js org?

[mliarakos]

There are scripted tests for the sbt plugin: https://github.com/akka-js/shocon/blob/master/travis/testSbtPlugin.sh

I was able to move everything to SBT 1.4.9 with tests passing. I didn't go beyond SBT 1.4.x to avoid dealing with versionScheme introduced in SBT 1.5.0 for the time being.

Totally fine if this is the direction the community is taking!

Bumped Scala.js to 1.8.0. Reviewing usage on Maven Central, it looks like many projects are moving Scala.js forward over time. In addition, this is all for akka-js/akka.js#129, which needs to update to Scala.js 1.8.0 anyway.

@mliarakos would you consider stepping up as a maintainer in the akka-js org?

I really appreciate the offer, but I don't have the time for the comitment right now. I'l let you know if that changes in the future.

[mliarakos]

Because of the big Scala.js bump, I bumped the library version to 1.1.0 rather than 1.0.1.