macos: support drag-and-drop and default file associations (#1822)

* macos: support drag-and-drop and default file associations

* resources/macos: use LSItemContentTypes to narrow down files

* macos: support opening folders

* rootview: workaround macos weird dnd event timing

* core/rootview: rename variable and refactor if statement

resources/macos/Info.plist.in

@@ -8,8 +8,32 @@
 	<string>lite-xl</string>
 	<key>CFBundleIconFile</key>
 	<string>icon.icns</string>
-  <key>CFBundleIdentifier</key>
-  <string>com.lite-xl</string>
+	<key>CFBundleDocumentTypes</key>
+	<array>
+		<dict>
+			<key>CFBundleTypeExtensions</key>
+			<array>
+			  <string>*</string>
+			</array>
+			<key>CFBundleTypeRole</key>
+			<string>Editor</string>
+			<key>NSDocumentClass</key>
+			<string>NSDocument</string>
+			<key>CFBundleTypeName</key>
+			<string>All Files</string>
+		</dict>
+	</array>
+	<key>LSItemContentTypes</key>
+	<array>
+		<string>public.text</string>
+		<string>public.folder</string>
+	</array>
+	<key>NSExportableTypes</key>
+	<array>
+		<string>public.text</string>
+	</array>
+	<key>CFBundleIdentifier</key>
+	<string>com.lite-xl</string>
 	<key>CFBundleName</key>
 	<string>Lite XL</string>
 	<key>CFBundlePackageType</key>