Restructure files for julia

repo2docker/buildpacks/__init__.py

@@ -2,7 +2,7 @@ from .base import BuildPack, BaseImage
 from .python import PythonBuildPack
 from .conda import CondaBuildPack
 from .julia import JuliaBuildPack
-from .julialegacy import JuliaLegacyBuildPack
+from .julia import JuliaLegacyBuildPack
 from .docker import DockerBuildPack
 from .legacy import LegacyBinderDockerBuildPack
 from .r import RBuildPack

repo2docker/buildpacks/julia/__init__.py

@@ -0,0 +1,2 @@
+from .julia_project import JuliaBuildPack
+from .julia_require import JuliaLegacyBuildPack