add convenience functions to sphinx documentations

[timmichelsen]

Add ts.fromtextfile http://scipy.org/scipy/scikits/browser/trunk/timeseries/scikits/timeseries/trecords.py

and all extras functions http://scipy.org/scipy/scikits/browser/trunk/timeseries/scikits/timeseries/extras.py

to the Sphinx documentation.

The good this ins that these can then be found throu the sphinx search.

Thanks.