plotter.decorators: removed unused import
setup.py: added scipy as package dependency
gwpy.__init__: removed explicit astropy references
Series: added __getslice__ to handle explicit [i:j] slices
TimeSeries: new filter method

    - generic filter application method using scipy.signal.lfilter underneath
    - moved highpass and lowpass to use new filter method for clarity
SpectrumAxes: changed linewidth on mmm
Array: fixed data ownership in Array.__pow__
Array2D: cleaned up __getitem__

    - func now more readable and probably more robust
Series: removed utterly redundant code
Plot.add_colorbar: apply coloring to all mappables
Spectrogram: multiple little bug fixes

    - added filter method for frequency-domain filtering
    - set maths operators to return Spectrum
    - bug fixes
Spectrum.filter: new generic filter method

    - Spectrum.filter handles frequency-domain filtering
    - deprecates Spectrum.filterba
plotter.core: added __all__
plotter: minor edits to __init__.py
StateVector: added plot method
Channel: added url property

    - holds URL to channel information system entry for this channel
Channel.query: store url from CIS query
plotter.table: rebuilt methods for plotting LIGO_LW tables

    - EventTablePlot: standard figure wrapper
    - EventTableAxes: minimal subclass of Axes that can unwrap table columns