text: Title: resample trajectory and hyp.tools.resample
  Body: While animated line plots are resampled, static plot are not.  We could add a `resample` flag to the `plot` function that allows a user to upsample (or downsample) their timeseries data. Then, we could expose the function as `hyp.tools.resample`. 
  
  questions: 
  
  + this only makes sense for timeseries data (I think), so do we allow the user to resample non-timeseries data?
  
  + how should the user interact with the flag? i.e. does 10 mean upsample by a factor of 10? what about downsampling?
  
  