Adds transmon calibration programs

[qci-chou]

• Adds repeated pi and pio2 pulse train calibration programs

[loganbvh]

Hi @qci-chou - at some point Black changed the way it formats the power operator (**) in some circumstances. The main branch hadn't been updated since this happened, so the formatting in the main branch was inconsistent with the rules of the current version of Black. I updated the main branch with #19 and then reformatted your branch with a89cfe3.

The new bounds for the fit_sine guess were causing some of the tests to fail, so I updated them here c4ae360.

I also had to change the number of tune_rabi() iterations in a couple of tests to get the tests to pass - not exactly sure why, but I think everything looks good now.

If the changes I made look okay to you, feel free to merge the PR