ENH: Create tubetk.pth.

This file is used to make TubeTK Python packages and modules importable in a
local Python installation.

Change-Id: Ib2b7793fdf7d1c8a4014705b7caa07b52e702813
ENH: Add infrastructure for testing Base/Python.

Change-Id: I363b5800f8a6b66d47bf7db50a8529482efffad1
ENH: Add ExtractTubePointsSpatialObjectFilter.

Add a filter to take a tree of tube SpatialObjects and extracts all the
points (TubeSpatialObjectPoint's or VesselTubeSpatialObjectPoint's) and
collects them into a single std::vector container.

Change-Id: I657371551a661c025bddf7e434949bdfef0af5c3
ENH: Convert tubes to NumPy arrays.

Write a C Python extension module to convert the VesselTubeSpatialObjectPoint's
in a file that contains a VesselTubeSpatialObject into a NumPy record array.
Each property in the tube point is a field in the NumPy record array.  The
length of the array equals the number of points in the tube. Example code:

  from tubetk.numpy import tubes_from_file
  tubes = tubes_from_file(filename)
  print(tubes['Radius'])

To make importable:

1) Turn TubeTK_USE_NumPy ON in the CMake configuration.
2) Make a symlink to /path/to/TubeTK-build/Python/Base/tubetk.pth at $(python -m site --user-site).

Todo's:

1) Support 2D.
2) Do not include VesselTubeSpatialObject fields for a TubeSpatialObject.

Change-Id: If9e321e2a3f6d81644382917e8bbcac0536c6685
ENH: Visualize tube points as circles.

Visualize tube points as circles.  This captures the tube point size,
orientation, position, and an alpha value on the color can be used to indicate
the weight when performing registration, etc.

Tube points are visualized with pyqtgraph by creating pyqtgraph MeshData out
of circles.  The circles are created from a wagonwheel representation of
vertexes and faces.  A circle is created in the x-y plane, scaled with the
tube point Radius, rotated via the tube point Normal1, Normal2, and Tangent, and
translated using the tube point Position.

Change-Id: If04c6527f3acd666a5f8395576bbeb9b1c9f4d76
Merge topic 'TubeVis3'

d905765 ENH: Visualize tube points as circles.
c461ba7 ENH: Convert tubes to NumPy arrays.
6b5e15e ENH: Add ExtractTubePointsSpatialObjectFilter.
4bebf6f ENH: Add infrastructure for testing Base/Python.
963e2d0 ENH: Create tubetk.pth.