SciDAVis - Improvements SVN-temp

- Documented classes Filter, Differentiation, Integration, Interpolation,
SmoothFilter, FFTFilter, FFT, Correlation, Convolution and Deconvolution.
- Improved documentation of success/failure flags returned by some methods.

The relevant parts of the Python API (i.e. excluding some parts which are used
internally but do not make much sense in scripts) should be all covered now;
which is not to say that there isn't plenty of room for improvement.

- Implemented extraction of Integration result from Python.
- Deprecated Filter.setColor(string), for the same reason Fit.setColor(string)
has been deprecated a while back.

- Documented classes ExponentialFit, TwoExpFit, ThreeExpFit, SigmoidalFit,
GaussAmpFit, NonLinearFit, PluginFit, LorentzFit, GaussFit, PolynomialFit and
LinearFit.

- Fixed bug in Python interface to PolynomialFit.

- Fixed bug in Python interface to LorentzFit.

- Section on Savitzky-Golay smoothing rewritten to provide better background
information on the algorithm. Corrected formula, which contained several
errors.
- Corrected title of FFT smoothing section.

- Added (non-closing) apply button to FunctionDialog.

- Corrected typo in API documentation.

- Reconcidered handling of edges in Savitzky-Golay smoothing.
While the new behaviour arguably does have benefits, the legacy zero-padding
approach isn't strictly wrong. On the whole, changing this between bugfix
releases is probably more annoying than sticking with a slightly inferior
solution (for now).
=> rewritten Savitzky-Golay code changed to use zero padding

- Corrected several technical issues in the manual. Should compile (using Makefile) now.