Respect blockquotes for filling and movement

fill-paragraph now respects paragraph boundaries within
blockquotes.  Similarly, forward-paragraph now stops
at blank lines within blockquotes.

markdown-mode.el

@@ -6615,6 +6615,7 @@ or \\[markdown-toggle-inline-images]."
                   '(
                     "\f" ; starts with a literal line-feed
                     "[ \t\f]*$" ; space-only line
+                    "\\(?:[ \t]*>\\)+[ \t\f]*$"; empty line in blockquote
                     "[ \t]*[*+-][ \t]+" ; unordered list item
                     "[ \t]*\\(?:[0-9]+\\|#\\)\\.[ \t]+" ; ordered list item
                     "[ \t]*\\[\\S-*\\]:[ \t]+" ; link ref def
@@ -6627,6 +6628,7 @@ or \\[markdown-toggle-inline-images]."
    (make-local-variable 'paragraph-separate)
    (mapconcat #'identity
               '("[ \t\f]*$" ; space-only line
+                "\\(?:[ \t]*>\\)+[ \t\f]*$"; empty line in blockquote
                 ;; The following is not ideal, but the Fill customization
                 ;; options really only handle paragraph-starting prefixes,
                 ;; not paragraph-ending suffixes:

tests/markdown-test.el

@@ -3301,6 +3301,15 @@ date = 2015-08-13 11:35:25 EST
    (markdown-beginning-of-block)
    (should (= (point) (point-min)))))
 
+(ert-deftest test-markdown-movement/blockquote-paragraphs ()
+  "Test filling of blockquotes containing multiple paragraphs."
+  (markdown-test-string "> Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.\n>\n> Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.\n"
+    (forward-paragraph)
+    (should (looking-at "^>$"))
+    (should (= (point) 128))
+    (forward-paragraph)
+    (should (= (point) (point-max)))))
+
 (ert-deftest test-markdown-movement/reference-definition ()
   "Test jumping to reference definitions."
   ;; Jumping to explicit reference definition
@@ -3461,6 +3470,13 @@ See `adaptive-fill-first-line-regexp'."
    (fill-paragraph)
    (should (string-equal (buffer-string) "> Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do\n> eiusmod tempor incididunt ut labore et dolore magna aliqua."))))
 
+(ert-deftest test-markdown-filling/blockquote-paragraphs ()
+  "Test filling of blockquotes containing multiple paragraphs."
+  (markdown-test-string "> Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.\n>\n> Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.\n"
+   (forward-paragraph)
+   (fill-paragraph)
+   (should (string-equal (buffer-string) "> Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.\n>\n> Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris\n> nisi ut aliquip ex ea commodo consequat.\n"))))
+
 (ert-deftest test-markdown-filling/space-after-list-marker ()
   "`fill-paragraph' should preserve more than one space after a list marker,
 since users may wish to indent their lists more than one space more than the