ENH: Add a 1D Savitzky-Golay filter
DOC: signal: fixed the last example in the docstring for savgol_coeffs
DOC: signal: fixed a typo in the savgol_filter docstring
DOC: signal: fix typo in _fit_edge docstring
BUG: signal: in savgol_filter, properly handle dtypes that are not 32 or 64 bit floating point
Merge pull request #470 from WarrenWeckesser/savgol2

ENH: signal: Add a 1D Savitzky-Golay filter