CLN: ASV plotting
Flake8'd and simplified some of the setup. 

```
$ asv dev -b ^plotting
· Discovering benchmarks
· Running 6 total benchmarks (1 commits * 1 environments * 6 benchmarks)
[  0.00%] ·· Building for existing-py_home_matt_anaconda_envs_pandas_dev_bin_python
[  0.00%] ·· Benchmarking existing-py_home_matt_anaconda_envs_pandas_dev_bin_python
[ 16.67%] ··· Running plotting.Misc.time_plot_andrews_curves              1.92s
[ 33.33%] ··· Running plotting.Plotting.time_frame_plot                   417ms
[ 50.00%] ··· Running plotting.Plotting.time_series_plot                  418ms
[ 66.67%] ··· Running ...ting.TimeseriesPlotting.time_plot_irregular      130ms
[ 83.33%] ··· Running plotting.TimeseriesPlotting.time_plot_regular       388ms
[100.00%] ··· Running ...TimeseriesPlotting.time_plot_regular_compat      123ms
```
