Make two small fixes to the quoting feature

Summary:
Ref T4119.

  - Trim newlines off the quoted text before quoting it; otherwise we can end up with a staircase of ">" at the end of a quote.
  - Allow image macros to have leading whitespace, so multiple consecuitive quoted macros work properly.

Test Plan: I QUOTED MACROS A LOT OF TIMES

Reviewers: btrahan, chad

Reviewed By: chad

Subscribers: epriestley

Maniphest Tasks: T4119

Differential Revision: https://secure.phabricator.com/D8983

src/applications/macro/remarkup/PhabricatorRemarkupRuleImageMacro.php

@@ -12,7 +12,7 @@ final class PhabricatorRemarkupRuleImageMacro
 
   public function apply($text) {
     return preg_replace_callback(
-      '@^([a-zA-Z0-9:_\-]+)$@m',
+      '@^\s*([a-zA-Z0-9:_\-]+)$@m',
       array($this, 'markupImageMacro'),
       $text);
   }

src/applications/transactions/controller/PhabricatorApplicationTransactionCommentQuoteController.php

@@ -34,6 +34,7 @@ final class PhabricatorApplicationTransactionCommentQuoteController
     }
 
     $content = $xaction->getComment()->getContent();
+    $content = rtrim($content, "\r\n");
     $content = phutil_split_lines($content, true);
     foreach ($content as $key => $line) {
       if (strlen($line) && ($line[0] != '>')) {