added new frequency plots and code

[skhnat]

1) Changed code to average a spectrogram over 20 seconds in the hamming window. Also interpolated all signals to the same sampling rate and clipped out the sections that were not under the influence of longitudinal perturbations 2) Changed "dusty purple" to "red" in each code and updated legend 3) Edited the text in the report to reflect the results in the new graphs 4) Fonts are still strange when saving to pdf

[moorepants]

Looks fine other than the two notes I wrote, you can merge after fixing them.