id -> potID

id is a python method. We should avoid replacing these.
* timestream/manipulate/plantSegmenter.py (ImagePotHandler__init__): id->potID
Add softBindings

* timestream/manipulate/plantSegmenter.py (ImagePotHandler): Add softBindings
dictionary. This will contain relations of the pot to other elements in other
contexts. This will set us up for relating pot ID to chamber ID and will
ultimately allow de-randomization.
Add ImagePotRectangle class.

* timestream/manipulate/pipecomponents.py (plantExtractor.__call__): Perform the
growM calculation at this stage instead of in the ImagePotMatrix class.
* timestream/manipulate/plantSegmenter.py (ImagePotRectangle): New class with
all the nitty gritty calculations for rectangles in images.
(ImagePotHandler): Put all the rectangle previously contained in ImagePotHandler
in the new ImagePotRectangle.
Remove "trays" from ImagePotMatrix

ImagePotMatrix will organize pots by ID, not by tray. The tray information can
still by added as an additional binding.
* timestream/manipulate/pipecomponents.py (PotDetector.__call__): Create the
ImagePotMatrix as soon as we detect the pots in PotDetector.
(PlantExtractor): We now expect a ImagePotMatrix object in the arguments.
* timestream/manipulate/plantSegmenter.py (ImagePotHandleriphPrev): We put this
in a property and use _iphPrev internally.
(ImagePotHandler.setSbind): Allows the creation of an arbitrary binding for each
pot.
(ImagePotMatrix): We remove the tray class and have a simple dictionary of pots
indexed by the potId.
(ImagePotMatrix.addPot): New method that adds pots to the matrix dictionary.
Add tray binding to each pot

* timestream/manipulate/pipecomponents.py (PotDetector.__call__): Add tray id
for each pot.
* timestream/manipulate/plantSegmenter.py (setSbind): Fix error in var name.
Create a new file timestrea/manipulate/pot.py

This will have the pot related logic.
* timestream/manipulate/pipecomponents.py: Remove pot related logic
* timestream/manipulate/pot.py: Copy paste from pipecomponents.py