Vim-plug cleanup

Removed vim-plug from VCS, added method to automatically download
vim-plug.

.gitignore

@@ -4,3 +4,4 @@ bundle/*
 view/*
 tags
 .netrwhist
+autoload/plug.vim

vimrc

@@ -3,6 +3,12 @@ set nocompatible                    "VIM over VI
 
 " vimplug conf {{{
 
+if empty(glob('~/.vim/autoload/plug.vim'))
+    silent !curl -fLo ~/.vim/autoload/plug.vim --create-dirs
+                \ https://raw.githubusercontent.com/junegunn/vim-plug/master/plug.vim
+    autocmd VimEnter * PlugInstall --sync | source $MYVIMRC
+endif
+
 call plug#begin('~/.vim/bundle')
 
 Plug 'Rykka/riv.vim'