Revised version.md

Revised version by Wenke Ren

Bug Fixing

1. In function QSOFit._DoLineFit(), if there is no line to fit while user wanna a figure to plot, an error would be raised due to the undefined self.gauss_result et al.
2. The parameter setting in example.ipynb constrained the core and the wing component of [OIII] doublet to a single same values instead of two values respectively.
3. The function QSOFit._do_tie_line() could not full fill the function described in generate_par_file() in example.ipynb. I split the tie procedure of windex to make sure the tie of line width independent from velocity offset.
4. Adjust the code style according to google python style guide.

New Features

1. Regulate the form of the output data instead of a string for all.

2. Add the normalization factor and velocity shift of FeII template and the normalization factor and $\tau_e$ of Balmer continuum into output, so that one can rebuild the fitting model acconting the output result.

3. FeII flux calculation. An optional function which is compatible with former programs.

4. **(High Risk): **Overall re-wright the QSOFit._PlotFig() for the convenience of modification and add a $\chi^2$ parameter on the left top.

5. Move all function inside the class QSOFit.