[tools/xmlparser] Fix from_csv single str val read

Closes #295

When reading a single string value from csv
which is containing commata, make sure,
that it still remains a single string value
and is not split up into a multi value at
the comma positions.

Author: mpsonntag

odml/tools/xmlparser.py

@@ -40,8 +40,14 @@ def to_csv(val):
 def from_csv(value_string):
     if not value_string:
         return []
-    if value_string[0] == "[":
+    if value_string[0] == "[" and value_string[-1] == "]":
         value_string = value_string[1:-1]
+    else:
+        # This is a single string entry, any comma contained
+        # is part of the value and must not be used to
+        # split up the string.
+        return [value_string]
+
     if not value_string:
         return []
     stream = StringIO(value_string)