🐛 Don't cache dict in bibdatabase (#348)

Attention: Multiple calls to get_entries_dict() now lead to multiple creations of the dict. For huge databases, one may thus want to avoid doing that.

bibtexparser/bibdatabase.py

@@ -86,17 +86,15 @@ def entry_sort_key(entry, fields):
             result.append(str(entry.get(field, '')).lower())  # Sorting always as string
         return tuple(result)
 
-    def _make_entries_dict(self):
-        for entry in self.entries:
-            self._entries_dict[entry['ID']] = entry
-
     def get_entry_dict(self):
-        """Return a dictionary of BibTeX entries.
-        The dict key is the BibTeX entry key
+        """Return a dictionary of BibTeX entries, where dict key is the BibTeX entry key.
+        
+        This method re-creates the dict every time it is called,
+        hence subsequent calls should be avoided with large databases.
         """
-        # If the hash has never been made, make it
-        if not self._entries_dict:
-            self._make_entries_dict()
+        self._entries_dict = dict()
+        for entry in self.entries:
+            self._entries_dict[entry['ID']] = entry
         return self._entries_dict
 
     entries_dict = property(get_entry_dict)