Support SBT 1.x

[ngocdaothanh]

Xitrum doesn't support SBT 1.x yet, because it's calculating program's root directory like this:

  lazy val root = {
    // Support the case when Xitrum is used in a SBT multimodule project, see:
    // https://github.com/xitrum-framework/xitrum/issues/47

    // Don't use application.conf, because Akka .jar file also include it
    val url = Thread.currentThread.getContextClassLoader.getResource("xitrum.conf")
    if (url != null) {
      val fileName = url.getFile
      // Use "/" instead of File.separator because "/" is always used in fileName,
      // even on Windows
      fileName.replace("/config/xitrum.conf", "")
    } else {
      // Fallback to current working directory
      System.getProperty("user.dir")
    }
  }

The code works with SBT 0.13.x, but not with SBT 1.2.1 (latest version as of September 2, 2018):
sbt/sbt#4340

[ngocdaothanh]

As commented in the linked SBT issue, sbt fgRun should be used instead of sbt run.

[ngocdaothanh]

Example to use Xitrum in an SBT 1.x project:
xitrum-framework/xitrum-new@317e626

[ngocdaothanh]

Announcement: https://groups.google.com/forum/#!topic/xitrum-framework/Mpx7wAPetq8