Fixes in log.py to allow a non-list logstream argument.
Fixed args.py to use the new data_format_path option

This replaces the deprecated data_base_directory option, which
was removed earlier with the enumerate update and replaced with
a more flexible data_format_path option, which allows for custom
paths to data files.
Added warn=False to matplotlib backend command

Added warn=False to suppress warnings caused by calling the
matplotlib backend setting command twice. This should not
affect the setting of the backend itself.
Changes: allow undef data type, added date field

Modified enumerate.py to allow an undefined data type. This is
particularly useful for custom parsers. Also added a date field
for enumerate to allow parsers to extract the date information
from a particular file.

Finally, added a warning about the deprecation of enumerate_all.
This function (and its corresponding arguments and options
elsewhere) will be removed in the near future.
Actually added message about enumerate_all deprecation