Move to Gradle build

We should be using a Gradle build, so here is a conversion to that.  Moved files to correct directory tree, added build files, fixed some tests that were flakey (ordering of attributes could change) and these tests were running differently in Gradle vs. IntelliJ, removed old IntelliJ project files, added gradle wrapper files.  Does everything but publish the maven artifact at the end.  Eventually we should have a common kotlinx build that builds the sub projects using a common base setup, we can create that in a future step.