Revert "[org] Add epub support"

This reverts commit 238be0227b.

CHANGELOG.develop

@@ -1743,7 +1743,6 @@ Other:
 - Added the org-mode keybindings to the org-journal major mode (thanks to Marty
   Buchaus)
 - Replace ox-reveal with org-re-reveal (thanks to Magnus Therning)
-- Added epub support (thanks to vishvanath45)
 **** Osx
 - Fixed OSX mapping issue (thanks to Joey Liu)
 - Added layer variables to customize modifier behaviors on macOS:

layers/+emacs/org/README.org

@@ -20,7 +20,6 @@
   - [[#project-support][Project support]]
   - [[#org-brain-support][Org-brain support]]
   - [[#mode-line-support][Mode line support]]
-  - [[#epub-support][Epub support]]
 - [[#key-bindings][Key bindings]]
   - [[#starting-org-mode][Starting org-mode]]
   - [[#toggles][Toggles]]
@@ -291,16 +290,6 @@ To permanently enable mode line display of org clock, add this snippet to your
   (setq spaceline-org-clock-p t)
 #+END_SRC
 
-** Epub support
-To install the Org exporter [[https://github.com/ofosos/ox-epub][ox-epub]] that generates e-book file format [[https://en.wikipedia.org/wiki/EPUB][epub]], set
-the variable =org-enable-epub-support= to =t=.
-
-#+BEGIN_SRC emacs-lisp
-  (setq-default dotspacemacs--configuration-layers
-                '((org :variables
-                       org-enable-epub-support t)))
-#+END_SRC
-
 * Key bindings
 ** Starting org-mode
 

layers/+emacs/org/packages.el

@@ -39,7 +39,6 @@
         persp-mode
         (ox-hugo :toggle org-enable-hugo-support)
         (org-trello :toggle org-enable-trello-support)
-        (ox-epub :toggle org-enable-epub-support)
         ))
 
 (defun org/post-init-company ()
@@ -716,7 +715,3 @@ Headline^^            Visit entry^^               Filter^^                    Da
         "mtdc" 'spacemacs/org-trello-pull-card
         "mtub" 'spacemacs/org-trello-push-buffer
         "mtuc" 'spacemacs/org-trello-push-card))))
-
-(defun org/init-ox-epub ()
-  (use-package ox-epub
-    :after ox))