rename "types" to "common" to avoid name conflict

types is already a standard python package

meshroom/common/__init__.py

@@ -0,0 +1,47 @@
+Model = None
+Slot = None
+Signal = None
+Property = None
+BaseObject = None
+
+if 1:  # TODO: switch types according to something
+    # PySide types
+    from .qt import Model, Slot, Signal, Property, BaseObject
+else:
+    # Core types
+    from .core import Model, Slot, Signal, Property, BaseObject
+
+
+class _BaseModel:
+    """ Common API for model implementation """
+
+    def __init__(self, keyAttrName="name", **kwargs):
+        """
+        :param keyAttrName: name of the attribute containing the unique key for an object
+        """
+        pass
+
+    @property
+    def objects(self):
+        """ Return a dictionary with {unique_key: object} mapping"""
+        return None
+
+    def get(self, key):
+        """ Get the object with the unique key 'key' """
+        pass
+
+    def add(self, obj):
+        """ Add given object using its 'keyAttrName' as unique key """
+        pass
+
+    def pop(self, key):
+        """ Remove 'item' with unique key 'key' from the model """
+        pass
+
+    def remove(self, obj):
+        """ Remove 'obj' from the model """
+        pass
+
+    def clear(self):
+        """ Remove all internal objects """
+        pass