lispy-pkg.el: Update dependencies

* lispy-pkg.el (hydra): Remove dependency.
(multiple-cursors): Remove dependency.

* lispy.el (defhydra): Add a stub macro that offers to install hydra and
  recompile/reload lispy when a hydra command is called.

Re #74
Fixes #46

lispy-pkg.el

@@ -1,8 +1,6 @@
 (define-package "lispy" "0.24.0"
   "vi-like Paredit"
   '((emacs "24.1")
-    (ace-window "0.8.0")
-    (hydra "0.12.1")
+    (ace-window "0.9.0")
     (iedit "0.97")
-    (multiple-cursors "1.3.0")
-    (swiper "0.2.0")))
+    (swiper "0.4.0")))

lispy.el

@@ -151,7 +151,6 @@
 (require 'lispy-inline)
 (require 'iedit)
 (require 'delsel)
-(require 'hydra)
 (require 'swiper)
 
 ;;* Customization
@@ -6188,6 +6187,19 @@ FUNC is obtained from (`lispy--insert-or-call' DEF PLIST)."
   ("f" lispy-flatten)
   ("a" lispy-teleport)))
 
+(unless (package-installed-p 'hydra)
+  (defmacro defhydra (name &rest _)
+    "This is a stub for uninstalled `hydra' package."
+    `(defun ,(intern (format "%S/body" name)) ()
+       (interactive)
+       (if (yes-or-no-p "Package `hydra' not installed. Install?")
+           (progn
+             (package-install 'hydra)
+             (save-window-excursion
+               (find-library "lispy")
+               (byte-compile-file (buffer-file-name) t)))
+         (error "Please install `hydra' and recompile/reinstall `lispy'")))))
+
 (defhydra lh-knight ()
   "knight"
   ("j" lispy-knight-down)