Merge pull request #316 from binsoftware/cocoa-fixes

Cocoa fixes: memory leaks, monitor handling, is_current()

src/x11/window/monitor.rs

@@ -2,6 +2,7 @@ use std::ptr;
 use std::collections::VecDeque;
 use super::super::ffi;
 use super::ensure_thread_init;
+use native_monitor::NativeMonitorId;
 
 pub struct MonitorID(pub u32);
 
@@ -43,6 +44,11 @@ impl MonitorID {
         Some(format!("Monitor #{}", screen_num))
     }
 
+    pub fn get_native_identifier(&self) -> NativeMonitorId {
+        let MonitorID(screen_num) = *self;
+        NativeMonitorId::Numeric(screen_num)
+    }
+
     pub fn get_dimensions(&self) -> (u32, u32) {
         let dimensions = unsafe {
             let display = ffi::XOpenDisplay(ptr::null());