Remove deprecated packages, mostly from Emacswiki

See: https://github.com/melpa/melpa/pull/5008
Add org-plus-contrib.

custom.el

@@ -10,7 +10,7 @@
  '(org-startup-truncated nil)
  '(package-selected-packages
    (quote
-    (flycheck solidity-mode sql-indent pip-requirements css-eldoc less-css-mode scss-mode sass-mode mmm-mode rainbow-mode tagedit yasnippet yagist ws-butler whole-line-or-region whitespace-cleanup-mode volatile-highlights unfill undo-tree switch-window smex smarty-mode smartparens rainbow-delimiters php-mode pandoc-mode page-break-lines ox-pandoc ox-gfm org-pomodoro multiple-cursors move-dup markdown-mode magit-gh-pulls json-mode js-comint iedit idomenu ido-completing-read+ highlight-symbol highlight-escape-sequences helm-swoop helm-gtags guide-key gitignore-mode github-clone github-browse-file gitconfig-mode git-timemachine git-messenger fullframe fill-column-indicator expand-region duplicate-thing dtrt-indent diminish csv-mode color-theme-sanityinc-tomorrow color-theme-sanityinc-solarized coffee-mode clean-aindent-mode bug-reference-github browse-kill-ring auto-complete anzu ace-jump-mode ac-js2))))
+    (org-plus-contrib org-contrib-plus flycheck solidity-mode sql-indent pip-requirements css-eldoc less-css-mode scss-mode sass-mode mmm-mode rainbow-mode tagedit yasnippet yagist ws-butler whole-line-or-region whitespace-cleanup-mode volatile-highlights unfill undo-tree switch-window smex smarty-mode smartparens rainbow-delimiters php-mode pandoc-mode page-break-lines ox-pandoc ox-gfm org-pomodoro multiple-cursors move-dup markdown-mode magit-gh-pulls json-mode js-comint iedit idomenu ido-completing-read+ highlight-symbol highlight-escape-sequences helm-swoop helm-gtags guide-key gitignore-mode github-clone github-browse-file gitconfig-mode git-timemachine git-messenger fullframe fill-column-indicator expand-region duplicate-thing dtrt-indent diminish csv-mode color-theme-sanityinc-tomorrow color-theme-sanityinc-solarized coffee-mode clean-aindent-mode bug-reference-github browse-kill-ring auto-complete anzu ace-jump-mode ac-js2))))
 (custom-set-faces
  ;; custom-set-faces was added by Custom.
  ;; If you edit it by hand, you could mess it up, so be careful.

lisp/init-org.el

@@ -1,5 +1,6 @@
 (when (< emacs-major-version 24)
   (require-package 'org))
+(require-package 'org-plus-contrib)
 
 (define-key global-map (kbd "C-c l") 'org-store-link)
 (define-key global-map (kbd "C-c a") 'org-agenda)