packaging: add help importing qstack_qml in __init__

qstack/__init__.py

@@ -9,10 +9,29 @@
 from qstack import mathutils
 from qstack import orcaio
 
+# qstack.regression needs sklearn to work
 try:
     import sklearn
 except ImportError:
     pass
 else:
     from qstack import regression
     del sklearn
+
+# qstack.qml is in a different python package
+# but prefer "the local version of it" if we are in a development environment, and both sources are there.
+import os
+_qstack_qml_path = os.path.join(os.path.dirname(__file__), 'qstack-qml')
+if os.path.isfile(os.path.join(_qstack_qml_path, 'qstack_qml', '__init__.py')):
+    import sys
+    sys.path.insert(0,_qstack_qml_path)
+    import qstack_qml as qml
+    sys.path.pop(0)
+    del sys
+else:
+    try:
+        import qstack_qml as qml
+    except ImportError:
+        pass
+del os, _qstack_qml_path
+