start breaking out a ui feature to set an input step (#253)

* start

* refactoring

* working

* version bump

src/ui/SetInputStep.js

@@ -0,0 +1,49 @@
+function setInputStepInit(_sequencer) {
+
+  return function setInputStep(options) {
+
+    var dropzone = $(options.dropZoneSelector);
+    var fileInput = $(options.fileInputSelector);
+ 
+    onLoad = options.onLoad;
+ 
+    var reader = new FileReader();
+ 
+    function handleFile(e) {
+ 
+      e.preventDefault();
+      e.stopPropagation(); // stops the browser from redirecting.
+ 
+      if (e.target && e.target.files) var file = e.target.files[0];
+      else var file = e.dataTransfer.files[0];
+      if(!file) return;
+ 
+      var reader = new FileReader();
+      
+      reader.onload = onLoad;
+ 
+      reader.readAsDataURL(file);
+    }
+ 
+    fileInput.on('change', handleFile);
+ 
+    dropzone[0].addEventListener('drop', handleFile, false);
+ 
+    dropzone.on('dragover', function onDragover(e) {
+      e.stopPropagation();
+      e.preventDefault();
+      e.dataTransfer.dropEffect = 'copy'; // Explicitly show this is a copy.
+    }, false);
+ 
+    dropzone.on('dragenter', function onDragEnter(e) {
+      dropzone.addClass('hover');
+    });
+ 
+    dropzone.on('dragleave', function onDragLeave(e) {
+      dropzone.removeClass('hover');
+    });
+
+  }
+
+}
+module.exports = setInputStepInit;