Moved hooke.libhookecurve -> hooke.curve and rewrote HookeCurve -> Curve class.

Moved hooke.libhookecurve -> hooke.curve and rewrote HookeCurve -> Curve class.

New class Data subclasses numpy.ndarray for faster data handling.

Changes:
  * hooke.libhookecurve.PlotObject -> hooke.ui.gui.plot.PlotObject
  * hooke.libhookecurve.Driver -> hooke.driver.Driver
  * Raise new exception hooke.driver.NotRecognized if no driver
    matches (vs. old print message and return false).
  * Curve stores data in a list (vs. old dict).  Often data order
    is important.  The names that used to key the data dict can
    now go into Data.info['name'].
  * HookeCurve.fits -> Curve.info['fits']
  * HookeCurve.plots is GUI data, but if the UI needs it, it should be
    stored in Curve.info['plots']
  * Since Curve.data is an array,
    HookeCurve.add_data() -> Curve.data.append(),
    HookeCurve.delete_data() -> Curve.data.remove(), and
    HookeCurve.set_data() -> Curve.data[i] = data