Suggested improvements to sigma_cont

[AstroRobin]

For generating contoured lines on plots with sigma_cont:

• It would good to merge this sigma_cont function with a function that also does filled contours if some "fill" flag is set. This will require some tweaking of the way you treat levels as in the filled case, they need to represent bounds of the filled regions.

• The default contour labels (clabel) could be set to the string versions of the percentiles given quite easily by multiplying by 100 and converting to a string. Would avoid mislabelled contours.

[MBravoS]

Thanks for the suggestions. The second one is implemented now in 0.2.3, together with a change from fractions to percentages for the values that percent accepts. The other one should be added in 0.2.4.

[MBravoS]

Filled option added as of version 0.5.0.