Develop (#16)

* Made it so that the image_parameters in get_image_parameters hold on to the functions instead of the function's return values.

In the get_image_generator() function there is now a single assignment of get_image_parameters into a dictionary of lambda functions that are used to update the image parameters each iteration.

* Update deeptrack.py

-Track non-square videos
-Fixed x,y in plot_tracked_scanning_boxes
-added option for elliptical particles in training
-fixed the resizing of the boxes in track_video (track_frame)
-added an option for preprocessing the images before tracking (normalise and enhance)

* Video files working in vlc

It seems that the issue with running the files in vlc was that the frame rate was too low. I increased the frame rate to 5 fps for all videos and tested in vls.

* Edit example notebooks

Edit example jupyter notebooks according to the changes made in deeptrack.py

* deeptrack.py updated again

in track_video and show_tracked_frames I took out the limit of showing maximum 10 frames since it interferes with the calculation of centroids of particles.

* All files updated

The updated files before resubmission in Optica.

* All the updated videos

The video updates for resubmission for Optica

* Update didn't save

This one didn't save before

* Not in the resubmission

* Not in the resubmission

* Updated under different name

This video has been added again as DeepTrack - Example 3 - Brownian Particles.mp4

* Not in the resubmission

Now there are two different trainings for example 4, one for bacteria and one for particles.

* no message

* Delete DeepTrack - Example 2 - Tracking single particle-checkpoint.ipynb

* Video name updated (#15)