Support loading multiple files or a folder from dropping on the Mac dock icon.

Fixes issue #2787

dist/Info.plist.in

@@ -44,6 +44,16 @@
   <string>30</string>
   <key>CFBundleDocumentTypes</key>
   <array>
+    <dict>
+      <key>CFBundleTypeOSTypes</key>
+      <array>
+        <string>****</string>
+        <string>fold</string>
+        <string>disk</string>
+      </array>
+      <key>CFBundleTypeRole</key>
+      <string>Viewer</string>
+    </dict>
     <dict>
       <key>CFBundleTypeExtensions</key>
       <array>

src/core/mac_startup.mm

@@ -153,6 +153,7 @@ static BreakpadRef InitBreakpad() {
     qLog(Warning)<<"Media key monitoring disabled";
 
 }
+
 - (BOOL) application: (NSApplication*)app openFile:(NSString*)filename {
   qDebug() << "Wants to open:" << [filename UTF8String];
 
@@ -163,6 +164,14 @@ static BreakpadRef InitBreakpad() {
   return NO;
 }
 
+- (void) application: (NSApplication*)app openFiles:(NSArray*)filenames {
+  qLog(Debug) << "Wants to open:";
+  NSLog(@"%@", filenames);
+  [filenames enumerateObjectsUsingBlock:^(id object, NSUInteger idx, BOOL* stop) {
+    [self application:app openFile:(NSString*)object];
+  }];
+}
+
 - (void) mediaKeyTap: (SPMediaKeyTap*)keyTap receivedMediaKeyEvent:(NSEvent*)event {
   NSAssert([event type] == NSSystemDefined && [event subtype] == SPSystemDefinedEventMediaKeys, @"Unexpected NSEvent in mediaKeyTap:receivedMediaKeyEvent:");