Customisable linestyles in performance profile plots

[DennisSoemers]

The primary reason for this PR is an added option for customising linestyles in performance profile plots. It works in exactly the same way as the colors parameter it already had; a map, None by default which means all methods are plotted as solid lines, but a map can be passed in to change the linestyles of every method's plot.

Here you can see, as an example, a plot I'm currently working on where I'm using this functionality to have some methods plotted as dotted lines instead of solid ones:

Additionally, I have added a .gitignore file to ignore some files that were automatically created when I installed rliable with pip from local source code in my own fork of the repo, and files created by working with rliable source code in the PyCharm IDE.

[agarwl]

Thanks for adding this, the profile plot indeed looks better. Merged by f9ef0a1.