Merge branch 'feature/linregress' into is24-master

* feature/linregress:
  optimized linregress to return a minimal timeseries whith two datapoints
  the calender in the composer can now be used to select dates in the future for prediction
  add numpy and scipy to the RPM requirements
  fix missing comma
  make linear regression available from the java script interface
  prune trailing whitespace
  register the linregress function
  fixing typos in test names
  better way to filter out None using np.not_equal
  initial implementation of the linregress