Use kwargs in add_timeseries_instance method.

Switching to using kwargs for setting attributes.
Use kwargs in ts_list method.

Switching to using kwargs for attribute access.
Git ignore DS_Store files.
Git ignore files created/used by the examples.
Separate out attribute kwargs parsing code.
Use kwargs in __get_ts_instance method.

Switching to using kwargs for attribute access.
Stop using get_measurand and get_source methods.
Remove unused get_measurand and get_source methods.
Use kwargs in __get_tsdb_file_by_id method.

Switching to using kwargs for attribute access.
Use kwargs in write method.

Switching to using kwargs for attribute access.
Use kwargs in read_all method.

Switching to using kwargs for attribute access.
Use kwargs in read_metadata method.

Switching to using kwargs for attribute access.
Remove outdated elements from docstrings.

Docstrings still require updating to properly reflect the new usage of
**kwargs instead of fixed 'measurand' and 'source' arguments.