added copy method to io.py

opendm/io.py

@@ -1,4 +1,5 @@
 import os
+import shutil, errno
 
 
 def get_files_list(path_dir):
@@ -30,3 +31,12 @@ def file_exists(path_file):
 
 def dir_exists(dirname):
     return os.path.isdir(dirname)
+
+
+def copy(src, dst):
+    try: 
+        shutil.copytree(src, dst)
+    except OSError as e:
+        if e.errno == errno.ENOTDIR:
+            shutil.copy(src, dst)
+        else: raise