Extension for the tube_calib module

It implements the described automatically guess for the fit parameters in
the getPoints method.

Reimplement getPoints method.

Implement getCalibratedPixelPositions using vectorial mathematics.

Conform the documentation to the rest

Change some of the parameters of getCalibration:

 * It does not deal with PeakFile but with PeakTable
 * Make PlotTube a list of values instead of a single one.
 * Remove some checkings, because it will be done at tube module.
 * Add the constructIdealTubeFromRealTube, previously in ideal_tube.

re #7387