version 0.3.0 release

version 0.3.0 - 20190821

• Added sampler with a variety of data-space sampling algorithms:
  • metropolis-hastings sampling as a multiserver tool
  • ray-based sampling using the 'Sampler' infrastructure
    • Sampler is a subclass of Renderer that supports integration with active-Vis operators
    • active-Vis operators to implement sampling based on isosurface crossing and significant changes to gradient
  • interpolation of a scalar field onto a set of samples (as a multiserver tool)
• Support for vector-valued volumes
  • added JSON format for volume description files that implements 'number of components' field
• Initial implementation of RungeKutta operator to trace streamlines in vector volumes
  • also 'TraceToPathLines' opewrtor to convert RungeKutta results to path lines for rendering
• Added schlieren to provide multi-hued Schlieren and shadowgraph-style rendering
  • also implemented 'float-image' output (in FITS format)
• Added ospray modules for class overrides to the underlying OSPRay rendering engine
• Separated data-generation and data-management tools into data from apps
• Added Docker containers:
  • galaxy: contains pre-built version of galaxy in CentOS linux
  • galaxy-base: contains pre-requisites for galaxy build in CentOS linux
• Added unit testing framework
• Renamed async app and associated source to gxyviewer
• Renamed vis app and associated source to gxywriter
• Renamed mh app and associated source to mhwriter
• Renamed amh app and associated source to mhviewer
• updated third-party/ispc to download v1.10.0
• updated third-party/embree to use v3.5.2
• updated third-party/ospray to use v1.7.3