specs2 1.13

`"specs2_2.10" % "1.12.3"` is **NOT** depends on Scala 2.10.0 final.

http://repo1.maven.org/maven2/org/specs2/specs2_2.10/1.12.3/specs2_2.10-1.12.3.pom

we should use 1.13 if use scala 2.10.0