Release Notes:
- improved testing with 90% test coverage
- VTK build added so ants visualization functions now work
- fix memory leak and remove need for garbage collection as in ANTsR by adding finalizer to py::capsule
- add (at least runtime) tests for all functionality
- added automatic travis build/test process for linux and mac with ITK caching
- add read-the-docs website
- added project source distribution to PyPI
- added wheels for very fast (< 1min) installation from scratch
- improved ANTs and ITK build process
- reduced repo size by having no third party code
- renamed library functions to LOCAL_ and WRAP_
- improved WRAP process
- removed cpp ANTsImage class so image.pointer is all that is passed to/from cpp
- improved import process by not calling lib module directly (only through utils)
- added better interface/initialization for ANTsImage class