adds cross building for scala 2.10 with play 2.3

This is useful for those of us still on scala 2.10 (slick is not yet out for 2.11 and so workflow can't make that jump quite yet).
Turn on cross releasing and unifiy scala 2.11 versions
Setting version to 0.1.3
Setting version to 0.1.4-SNAPSHOT
Add crossbuild for release step
Setting version to 0.1.4
Setting version to 0.1.5-SNAPSHOT
Update version in README
Merge pull request #6 from guardian/sw-play-2.3.2-scala-2.10

adds cross building for scala 2.10 with play 2.3