Get typing.NewType working (#1344)

Squashed from the following commits:

* Update pep0484.py

(I don't think I want to know why the cursor jumped to the beginning of the line with every keystroke in GitHub's online editor. Change was entered backwards.)

* Added test for inline use of NewType. Currently assuming that wrapped instances should get the underlying type.

* Altered tests per https://github.com/davidhalter/jedi/issues/1015#issuecomment-356131566

* Add NewTypeFunction to typing evaluation module

* Update AUTHORS.txt

* Add a new test, and a speculative justification

For now, address only the second comment

* Copy code from third comment on the PR

From inspection, I *believe* I understand what this code is doing, and as such, I believe this should cause the new test I added in response to the second comment to fail, because that test is based on faulty assumptions.

* Explicitly discard the key from the tuple

* Update pep0484_typing.py

* Test for the wrapped type, not the wrapper "type"

* Change the return value from calling a NewType

test/completion/pep0484_typing.py

@@ -256,6 +256,31 @@ for key in x.keys():
 for value in x.values():
     #? int()
     value
+
+WrappingType = typing.NewType('WrappingType', str) # Chosen arbitrarily
+y = WrappingType(0) # Per https://github.com/davidhalter/jedi/issues/1015#issuecomment-355795929
+#? str()
+y
+
+def testnewtype(y):
+    """
+    :type y: WrappingType
+    """
+    #? str()
+    y
+    #? ["upper"]
+    y.u
+
+WrappingType2 = typing.NewType()
+
+def testnewtype2(y):
+    """
+    :type y: WrappingType2
+    """
+    #?
+    y
+    #? []
+    y.
 # python >= 3.4
 
 class TestDefaultDict(typing.DefaultDict[str, int]):