Update to scala.js 1.x

[busti]

I am not certain if it will work like this...
But there is no example of this in the jitpack docs

[busti]

I have applied the change and squashed the two commits

[busti]

Sorry about that, my bash knowledge is a little rusty.
There also seems to be an error when downloading sbt-launcher, so I will try to get that fixed in this pr as well.

[busti]

Sorry for the spam. Everything should be in order now.
This PR now depends on fdietze/bench#20 which at this point is already merged.

This now also includes the following changes:

• updated maven central url
• updated scalatestplus to a version supporting scala.js 1.x
• updated bench to a version supporting scala.js 1.x

Quick note: The build log with output an error when running the second command. This is due to the jvm artifacts already being present. Unfortunately this error cannot be silenced due to sbt/sbt-pgp#124 . However, this does not cause any issues, the extra artifacts are discarded.

[busti]

The travis build failed with the following error:

[error] (benchJS / Test / scalaJSIR) org.scalajs.core.ir.IRVersionNotSupportedException: Failed to deserialize info of file compiled with Scala.js 1.0 (supported: 0.6.0, 0.6.13, 0.6.3, 0.6.17, 0.6.4, 0.6.6, 0.6.14, 0.6.8, 0.6.30, 0.6.29, 0.6.5, 0.6.15): /home/travis/.coursier/cache/v1/https/jitpack.io/com/github/fdietze/bench/bench_sjs0.6_2.11/5ffab44/bench_sjs0.6_2.11-5ffab44.jar:bench/util/package.sjsir

This is a problem in bench, but I do not have the slightest idea what could be causing it. The filename suggests that it was compiled with scala.js 0.6.x, but in the message it says that it was compiled with 1.0.
Maybe upgrading bench to 1.1 fixes this?

[fdietze]

I'm also fine with dropping 0.6 completely and only keeping scalajs 1.0. That would make things easier, I guess.

[busti]

@fdietze Sounds good, should I add that to this PR?

[fdietze]

@busti absolutely!

[busti]

@fdietze it is done

[fdietze]

@busti Thank you! I just gave you the permission to merge yourself.

[busti]

I suppose that's a solution. Consider it merged!