Add missing express module init

src/ifcopenshell-python/ifcopenshell/express/__init__.py

@@ -0,0 +1,20 @@
+import os
+import sys
+import subprocess
+
+d = os.path.abspath(os.path.dirname(__file__))
+sys.path.append(d)
+
+exp_parser_fn = os.path.join(d, "express_parser.py")
+
+if not os.path.exists(exp_parser_fn):
+    with open(exp_parser_fn, "w") as f:
+        subprocess.call([sys.executable, "bootstrap.py"], cwd=d, stdout=f)
+        
+import express_parser
+import schema_class
+import ifcopenshell.ifcopenshell_wrapper
+
+def parse(fn):
+    mapping = express_parser.parse(fn)
+    return schema_class.SchemaClass(mapping, schema_class.LateBoundSchemaInstantiator).code