Function: package-install-from-buffer

Install a package from the current buffer.
When called interactively, the current buffer is assumed to be a
single .el file that follows the packaging guidelines; see info
node `(elisp)Packaging'.

When called from Lisp, PKG-INFO is a vector describing the
information, of the type returned by `package-buffer-info'; and
TYPE is the package type (either `single' or `tar').