root path speaker matching

added data root path in speaker matching for mailabs, this way you don't need to start at the very bottom of the folder hierarchy if you want to explicitly define metafiles.

datasets/preprocess.py

@@ -82,14 +82,14 @@ def mailabs(root_path, meta_files=None):
     # meta_files = [f.strip() for f in meta_files.split(",")]
     items = []
     for idx, csv_file in enumerate(csv_files):
+        txt_file = os.path.join(root_path, csv_file)
         # determine speaker based on folder structure...
-        speaker_name_match = speaker_regex.search(csv_file)
+        speaker_name_match = speaker_regex.search(txt_file)
         if speaker_name_match is None:
             continue
         speaker_name = speaker_name_match.group("speaker_name")
         print(" | > {}".format(csv_file))
         folder = folders[idx]
-        txt_file = os.path.join(root_path, csv_file)
         with open(txt_file, 'r') as ttf:
             for line in ttf:
                 cols = line.split('|')