add support for NPY_LONGLONG conversions
add support for NPY_LONGLONG conversions

Note that we need to preserve the type (integer vs. float) even at the risk of overflow because many TF operations will fail if you change the type from integer to float.

rstudio/reticulate,rstudio/reticulate,terrytangyuan/reticulate,rstudio/tensorflow,terrytangyuan/reticulate,rstudio/reticulate,rstudio/reticulate,terrytangyuan/reticulate,rstudio/reticulate