update sbt version
add 'scala.' for import
Update xitrum 2.7 to 2.9
Update xitrum-scalate 1.1 to 1.2
Update sbt-launch.jar 0.12.4 to 0.13.0
Merge branch 'master' of https://github.com/georgeOsdDev/xitrum-placeholder
Update build.properties
Update plugins.sbt