{subtraction} Initial disk-subtraction commit

Assume -c, --corner argument means "find center dot and corner dots".
if -c,
    plot will include central and corner dots, so no separate filename
    threshargs only needs thresholds for large dots

	modified:   positions.py
{subtraction} New function `subtract_disks`

	modified:   positions.py
Rename function to `remove_disks`, change method

Uses positions to create mask `disks` of 1x1 pixel locations, which are
then eroded to be size of input disk kernel.  Multiplication by `disks`
mask removes large dots from original image.  Product is returned.

	modified:   positions.py
Add corners ipython pylab notebook

Testing ground, etc for center dot/disk removal, convolution, threshold labling, gaussian
fitting, and so on.

	new file:   corners.ipynb
Add TODO

To do list for the project.

	new file:   TODO
have to have extention for outliner

	renamed:    TODO -> TODO.otl
vimoutliner-ify

	modified:   TODO.otl
Lots of additions, cleanup, added times.

	modified:   TODO.otl
Remove disks a bit cleaner, disk now astype(int)

	modified:   positions.py
Finds the corners fully!

	modified:   corners.ipynb
Created gaussian disk function gdisk

	modified:   positions.py
convolve disk function

takes n for gaussian disk or a custom disk

	modified:   positions.py
Started label_particles_thresh function

Will be improve by removal of disks (or segments!), convolution, all
before threshold

	modified:   positions.py
TODO: use convolution/threshold for big dots too

	modified:   TODO.otl
Too much printing

	modified:   positions.py
Abbreviation actually adds more text.

of `segmentation` to `seg`

	modified:   positions.py
TODO: Fix high speed camera

	modified:   TODO.otl
Small changes

	modified:   corners.ipynb
IT WORKS!!!!!!!!!

	modified:   positions.py
Works!

	modified:   corners.ipynb