Machinevision-toolbox-python

* `Image` class
- `.dice` method, chops an image up into tiles, can be overlapping
- `.Tile(columns=0)` will arrange the tiles into a roughly square layout
- Constant images, previously many of these could only generate square images, this is now generalized
- `.Chequerboard` creates a chequerboard pattern
- set background color for image warp undefined pixels
- single plane images can have a colorplane name
- deprecate `colordict()`, use `colororder2dict()` instead
- `String` now supports two string formats, can create color images
- fixed bug with gamma="sRGB" which always returned a float image, type is now the same as passed

* Blobs

- new methods for blob aligned box, plot_aligned_box,
- `plot_perimeter` options
- `perimeter_hull` convex hull
- fixed bug with runt blobs

* Kernels

- added `Kernel.HGauss` for Hessian of Gaussian
- added `Kernel` repr method, `disp` method
ArUcoBoard class

* Camera models
- Fixed errors in some camera projection models

* Point clouds

- `PointCloud` now has a "constructor" for depth images, `PointCloud.DepthImage()`

* Miscellaneous

- Lots more code examples and plots
- Move decoratores scalar_result and array_result to machinevisiontoolbox.decorators.py
- improved unit testing

* `Kernel` methods now return `Kernel` instances rather than NumPy arrays. Methods that
accept a kernel can accept a `Kernel` instance or a NumPy array. Methods exist to
stringify or print a kernel.

* The indexing order of an `Image` object (using square bracket `__getitem__` access) has
changed and is now `img[u,v]` where `u` is the column coordinate and `v` is the row
coordinate. This is consistent with the column-first convention used across the
Toolbox and is consistent with the $(u,v)$ coordinate system for images. But, this
is the __opposite__ order to that used for NumPy index on the underlying array, and
to earlier versions of the Toolbox.

- a 2-tuple of integers, select this pixel. If the image has multiple planes, the
result is a vector over planes.
- a 3-tuple of integers, for a multiplane image select this pixel from the specified
plane.
- a 2-tuple of slice objects, select this region. If the image has multiple planes,
the result is a 3D array.
- a 3-tuple of slice objects, select this region of uv and planes
- an int, select this plane
- a string, select this named plane or planes

* added `pixel(u,v)` method for faster access to a single pixel value, scalar or vector.

* the children of a `Blob` is now given as a list of `Blob` objects, not their indices
within the overall list of blobs. This simplies traversing the blob hierarchy tree.
Similarly, the parent is a reference to the parent `Blob` object rather than an index,
and is `None` if the blob has no parent (its parent is the background).

* Documentation overhaul, both in-code docstrings, and the organization of the overall Sphinx document.

* Additional unit tests

* Myriad minor bug fixes, see commit history.