Upgrade to sbt 1.0.x

[suhasgaddam]

Closes #67

Scalafmt was not run on this code base. That seems like a specific choice by @andyscott.

  def overrideSwitchCommand: Command =
    Command.arb(Cross.requireSession(Cross.switchParser), CommandStrings.switchHelp)(switchCommandImpl)		

This snippet was using a lot of now private methods in sbt 1.0.

So I ended up copy pasting most of the required snippets into:
https://github.com/frees-io/iota/compare/sg-port-to-sbt-1.0.x#diff-c3b7f539f0c1b9fcb3c518e0704ae7eb

Is there a better way? If not, there needs to be appropriate license headers and attribution for that file. As far I can tell, they are compatible(BSD/ASLv2)... There are a few methods that were written under ASLv2(before the copy/paste).
https://github.com/sbt/sbt/blob/v1.0.1/main/src/main/scala/sbt/Cross.scala

[andyscott]

I can take a look at this soon-- probably today.

Regarding scalafmt: You're correct in that I specifically have it disabled. I don't think it does a very good job of auto formatting the general recursion code, macros, and some of the tests. But that's understandable as the code is on the more extreme side of Scala syntax.

[andyscott]

Could we leave this code in the same file as the AutoTLSPlugin file?

[suhasgaddam]

The only reason that I broke it out into anther file was due it being copy/pasted from a source with a different license than ours. Suggestions on how to properly attribute/license this copy/pasted code if it were in the same file? Same object(AutoTLSCross) in AutoTLSPlugin file with the attribution inside the object[is that enough/acceptable?]?

[andyscott]

I'd just add a comment above the copy/pasted code that links to the original source, indicates the original license, and then mentions that it's only copied here because there was no other easy way to achieve the same effect.

We could also reach out to the SBT team and confirm that it's okay, once we've made the changes.

[andyscott]

LGTM!