MAINT: Remove any imports from __init__ (hide __version__) (#38)

The helpers were just not needed and should be private.

`__version__` is a bit awkard and probably not quite right. Hiding
it seems good to me, I also changed it to look-up via `__name__`.

The thing is, I would like to vendor it, and then looking up `spatch`
is wrong and can fail. Looking up `__name__` may not actually be any
better, but for now I'll assume it is better than what we have.

Not sure if this matters either way, if it does we might have to find
a better solution...

Author: seberg

src/spatch/__init__.py

@@ -1,3 +1,7 @@
-from .utils import from_identifier, get_identifier, get_project_version
+def __getattr__(name):
+    if name == "__version__":
+        from .utils import get_project_version
 
-__version__ = get_project_version("spatch")
+        return get_project_version(__name__)
+
+    raise AttributeError(f"module {__name__!r} has no attribute {name!r}")

tests/test_general.py

@@ -0,0 +1,10 @@
+import spatch
+
+
+def test___version__():
+    # Sanity check that __version__ exists and returns
+    # something that faintly looks like a version string.
+    v = spatch.__version__
+    major, minor, *rest = v.split(".")
+    assert major.isdigit()
+    assert minor.isdigit()