Pome JS tests now part of build

Moved rdf/src to rdf/rdf_common_jvm/src so that IDE's work nicer. Otherwise, I have just got pome compiling OK and the tests pass.

I have also used my plugin https://github.com/InTheNow/sbt-scalajs that allows scalajs to test and compile as per a scala project - i,e

sbt test
The argument here is the same as the one for https://github.com/w3c/banana-rdf/commit/b8f4c076f52547af0627234e70b97f55454f6639 : There is no way we can submit changes that can be reviewed here if we don't allow all the projects' tests to be run on Travis, as seeing the test reports is key to allowing a reviewer to feel confident about the changes. This does not mean that the projects then need to be published all together. Publication is an off line event that can be made partial presumably by a bit of sbt coding. I suggest the build process be changed so that as much as possible be tested, but that a separate build process for publication be created. For example I would not suggest that rdfstorew nor pome yet be in the line for publication. But pome soon should not be that different from Plantain - and that will be obvious by looking at the code when done, as the differences between them will be minimal.