Is your feature request related to a problem? Please describe.
Currently libvips and openslide are hard requirements. There is functionality such as the annotations that do not require these requirements. SlideImage will likely not function without, but WsiAnnotations might.
Describe the solution you'd like
Allow to import the library without libvips and openslide available, openslide by itself can be an optional dependency, libvips should raise a warning
Is your feature request related to a problem? Please describe. Currently libvips and openslide are hard requirements. There is functionality such as the annotations that do not require these requirements. SlideImage will likely not function without, but WsiAnnotations might.
Describe the solution you'd like Allow to import the library without libvips and openslide available, openslide by itself can be an optional dependency, libvips should raise a warning