Incorporate Leaflet 0.5 changes into L.Control.Zoomslider.

src/L.Control.Zoomslider.js

@@ -7,14 +7,14 @@ L.Control.Zoomslider = L.Control.extend({
 
 	onAdd: function (map) {
 		var className = 'leaflet-control-zoomslider',
-			container = L.DomUtil.create('div', className);
+				container = L.DomUtil.create('div', className);
 
-        this._map = map;
+    this._map = map;
 
-		this._createButton('Zoom in', className + '-in'
+		this._zoomInButton = this._createButton('+', 'Zoom in', className + '-in'
 						   , container, this._zoomIn , this);
 		this._createSlider(className + '-slider', container, map);
-		this._createButton('Zoom out', className + '-out'
+		this._zoomOutButton = this._createButton('-', 'Zoom out', className + '-out'
 						   , container, this._zoomOut, this);
 
 		map.on('zoomend', this._snapToSliderValue, this);
@@ -69,15 +69,18 @@ L.Control.Zoomslider = L.Control.extend({
 	    this._map.zoomOut(e.shiftKey ? 3 : 1);
 	},
 
-	_createButton: function (title, className, container, fn, context) {
+	_createButton: function (html, title, className, container, fn, context) {
 		var link = L.DomUtil.create('a', className, container);
+		link.innerHTML = html;
 		link.href = '#';
 		link.title = title;
 
 		L.DomEvent
-			.on(link, 'click', L.DomEvent.stopPropagation)
-			.on(link, 'click', L.DomEvent.preventDefault)
-			.on(link, 'click', fn, context);
+		    .on(link, 'click', L.DomEvent.stopPropagation)
+		    .on(link, 'mousedown', L.DomEvent.stopPropagation)
+		    .on(link, 'dblclick', L.DomEvent.stopPropagation)
+		    .on(link, 'click', L.DomEvent.preventDefault)
+		    .on(link, 'click', fn, context);
 
 		return link;
 	},
@@ -129,6 +132,7 @@ L.Control.Zoomslider = L.Control.extend({
 	},
 
 	_snapToSliderValue: function(sliderValue) {
+		this._updateDisabled();
 		if(this._knob) {
 			sliderValue = isNaN(sliderValue)
 				? this._getSliderValue()
@@ -146,6 +150,21 @@ L.Control.Zoomslider = L.Control.extend({
 	},
 	_getSliderValue: function(){
 		return this._toSliderValue(this._map.getZoom());
+	},
+
+	_updateDisabled: function () {
+		var map = this._map,
+			className = 'leaflet-control-zoomslider-disabled';
+
+		L.DomUtil.removeClass(this._zoomInButton, className);
+		L.DomUtil.removeClass(this._zoomOutButton, className);
+
+		if (map._zoom === map.getMinZoom()) {
+			L.DomUtil.addClass(this._zoomOutButton, className);
+		}
+		if (map._zoom === map.getMaxZoom()) {
+			L.DomUtil.addClass(this._zoomInButton, className);
+		}
 	}
 });