Package and namespace changes

The jar file group and package names have been shortened to remove scalajs-reaction from the names. This makes it easier to specify them in your build.sbt file.

The package hierarchy has also changed. Since you are only likely to include one react package in your application the use of "ttg" was burdonsome. For most of the core packages, the ttg package prefix has been removed. For example instead of importing import ttg.react._ you would now just do import react._.