Currently my whole work cycle is:
Well, you should use SBT. You don't need to write anything for it: it will create everything you need for a basic project, and only ask you what is the project name and what version of Scala you'll be using.
After that, just put the files in the correct places. Look up the directory layout, though the short answer is main source files in
src/main/scala and test source files in
src/test/scala. You will have to create a very small "makefile" to get a test library in, though.