add compatability for neovim < 0.5

.vimrc

@@ -1,5 +1,10 @@
 " Modeline and Notes {
 " Environment {
+    " get current neovim version
+    if has('nvim')
+        let g:nvim_version = matchstr(execute('version'), 'NVIM v\zs[^\n]*')
+    endif
+
     " The default leader is '\', but many people prefer ',' as it's in a standard
     let mapleader = ','
     let maplocalleader = '_'

.vimrc.bundles

@@ -157,7 +157,7 @@
     
         " has('nvim') check if it's running on nvim rather than 
         " having neovim on your machine 
-        if isdirectory(expand(plugin_dir . "/github-nvim-theme")) && has('nvim')
+        if isdirectory(expand(plugin_dir . "/github-nvim-theme")) && has('nvim') && str2float(g:nvim_version) >= 0.5
             let g:github_function_style = "italic"
             "let g:github_sidebars = ["qf", "vista_kind", "terminal", "packer"]
             colorscheme github_dark
@@ -167,19 +167,20 @@
                 " Inversion
                 if g:colors_name == "github_light"
                     colorscheme github_dark
+                    :AirlineTheme afterglow
                 else
                     colorscheme github_light
+                    :AirlineTheme silver
                 endif
             endfunction
 
             noremap <leader>bg :call ToggleBG()<CR>
-        endif
     " }    
      
     " {
     " vim theme 
-        "if isdirectory(expand(plugin_dir . "/jellybeans.vim")) && !has('nvim')
-        if isdirectory(expand(plugin_dir . "/vim-afterglow")) && !has('nvim')
+    "elseif isdirectory(expand(plugin_dir . "/jellybeans.vim")) && !has('nvim')
+    elseif isdirectory(expand(plugin_dir . "/vim-afterglow"))
             colorscheme afterglow 
             let g:airline_theme='afterglow'
 
@@ -189,12 +190,10 @@
                 if g:colors_name == "afterglow"
                     set background=light
                     colorscheme PaperColor
-                    "let g:airline_theme='papercolor'
                     :AirlineTheme papercolor
                 else
                     set background=dark
                     colorscheme afterglow
-                    "let g:airline_theme='afterglow'
                     :AirlineTheme afterglow
                 endif
             endfunction