Changed the 'DOTFILES_DIR' env var to use '${HOME}/.dotfiles' instead…

… of '${HOME}/.bin-oss'. (vraravam#22)

* Added 'rsync'
* Add keybase to base install
* Moved setting up of login items toward the end of the script

Fix issue when running in a fresh/vanilla machine since 'ZDOTDIR' was…

… undefined.

'install-dotfiles' script can now handle multiple env vars