Added file option to import image to current layer

views/main-menu.hbs

@@ -6,6 +6,7 @@
 			<li><button>New</button></li>
 			<li><button>Save project</button></li>
 			<li><button>Open</button></li>
+			<li><button>Import</button></li>
 			<li><button id="export-button" class="disabled">Export</button></li>
 			<li><a href="https://lospec.com/pixel-editor">Exit</a></li>
 		</ul>