Update ScalatraBootstrap in skinny-blank-app
version 1.2.4

 - [blank-app] Add ./skinny task:clean command
 - [blank-app] Add ./skinny task:run command
 - [blank-app] Jetty 9.2.2
 - [common] joda-time 2.3 -> 2.4
 - [common] scala-parser-combinators 1.0.1 -> 1.0.2 (SI-7710)
 - [framework] Add JSON vulnerability protected JSON parser in JSONStringOps by @namutaka
 - [framework] Add JSONStringOps#***AsIs methods for skipping JSON key conversions
 - [orm] ScalikeJDBC 2.0.6 -> 2.0.7
 - [test] Add ThreadLocalDBAutoRollback with ScalaTest by @namutaka