Add scala cross building to runtests script
Use sbt 0.13.5-RC1 in templates project
Include template tests in runtests script

Signed-off-by: Rich Dougherty <rich@rd.gen.nz>
Avoid recompiling java-only projects when switching scala version
Avoid recompiling the sbt plugin when switching scala versions
Merge pull request #2807 from pvlugter/test-templates

Include template tests in runtests script