[pymtl] fixed __init__ to import user visible classes
[pymtl] fixed __init__ to import user visible classes

jjffryan/pymtl,12yujim/pymtl,jck/pymtl,tj93/pymtl,Abhinav117/pymtl,cfelton/pymtl,jck/pymtl,jjffryan/pymtl,Glyfina-Fernando/pymtl,12yujim/pymtl,tj93/pymtl,Glyfina-Fernando/pymtl,cfelton/pymtl,Glyfina-Fernando/pymtl,12yujim/pymtl,Abhinav117/pymtl,cfelton/pymtl,Abhinav117/pymtl,cornell-brg/pymtl,jck/pymtl,Abhinav117/pymtl,tj93/pymtl,cornell-brg/pymtl,cornell-brg/pymtl,jjffryan/pymtl