More tweaks for stable release

The default compiler flags in voro++'s config.mk file do not include
-fPIC, which makes it incompatible with building the shared object for
the python wrapper.

This reverts commit 4e97b575.

when recomputing special bonds, make certain we do not shrink atom->maxspecial and add force->special_extra only once

Final tweaks and doc changes for stable release

correctly use the term CUDA (instead of Cuda) when not referring to the KOKKOS device flag (which is Cuda)

Final build system changes for stable release

remove attempts to use urllib and use curl for all downloading. restore printing help with no flags.

- remove cross compiler stuff
- make use of Install.py consistent
- provide options for Makefile.serial and Makefile.mpi that match those in src

Installation scripts and docs reviewed for release

Adds tutorial for using LAMMPS in Bash on Windows

Fixed typo in "compute_voronoi_atom.txt"

There was the typo "requiers" in the Restrictions section of compute_voronoi_atom.txt.

- build into local directory to replace existing installation is now default
- add wrapper function that calls curl in case python package has not ssl support
- have to specify -n flag to avoid wiping out the existing installation
- can specify -p to point to an existing kim-api installation (implies -n)