BMesh: Boolean as an edit-mode tool

Works much the same as intersect operator,
expose as a new operator since for users its quite different.

Access from face menu.

Internally, this adds boolean args to BM_mesh_intersect function.

release/scripts/startup/bl_ui/space_view3d.py

@@ -2380,6 +2380,7 @@ class VIEW3D_MT_edit_mesh_faces(Menu):
         layout.operator("mesh.bevel").vertex_only = False
         layout.operator("mesh.solidify")
         layout.operator("mesh.intersect")
+        layout.operator("mesh.intersect_boolean")
         layout.operator("mesh.wireframe")
 
         layout.separator()