Fix compilation errors on Mac

NSUInteger was defined by older wxWidgets versions but is removed
in newer versions, so this would fail to compile when not using
wxWidgets from a subproject.

In font_file_lister_coretext.mm, some mac version number defines
in wxWidgets were clashing with static const variables for the same
version numbers in AppKit. Moving the wx includes after the AppKit
include works around this for now.

src/dialog_colorpicker.cpp

@@ -397,8 +397,8 @@ void ColorPickerScreenDropper::DropFromScreenXY(int x, int y) {
 	CGGetDisplaysWithPoint(CGPointMake(x, y), 1, &display_id, &display_count);
 
 	agi::scoped_holder<CGImageRef> img(CGDisplayCreateImageForRect(display_id, CGRectMake(x - resx / 2, y - resy / 2, resx, resy)), CGImageRelease);
-	NSUInteger width = CGImageGetWidth(img);
-	NSUInteger height = CGImageGetHeight(img);
+	size_t width = CGImageGetWidth(img);
+	size_t height = CGImageGetHeight(img);
 	std::vector<uint8_t> imgdata(height * width * 4);
 
 	agi::scoped_holder<CGColorSpaceRef> colorspace(CGColorSpaceCreateDeviceRGB(), CGColorSpaceRelease);

src/font_file_lister_coretext.mm

@@ -14,11 +14,11 @@
 //
 // Aegisub Project http://www.aegisub.org/
 
-#include "font_file_lister.h"
-
 #include <AppKit/AppKit.h>
 #include <CoreText/CoreText.h>
 
+#include "font_file_lister.h"
+
 namespace {
 struct FontMatch {
 	NSURL *url = nil;