#77 add dynamic get method to ViewService

[MariusWirtz]

new get method in ViewService returns MDX or NativeView:

from TM1py import TM1Service

with TM1Service(address='10.77.19.60', port=12354, user='admin', password='apple', ssl=True) as tm1:
    view = tm1.cubes.views.get(
        cube_name="Project Planning",
        view_name="I am a MDX View",
        private=False)
    view = tm1.cubes.views.get(
        cube_name="Project Planning",
        view_name="I am a Native View",
        private=False)

solves #77