fix(inspector): added close button to inspector modal, fixes #3213

public/app/partials/inspector.html

@@ -10,6 +10,9 @@
 			</div>
 		</div>
 
+		<button class="gf-box-header-close-btn" ng-click="dismiss();">
+			<i class="fa fa-remove"></i>
+		</button>
 	</div>
 
 	<div class="gf-box-body">