[#16] Add documentation, stubs for future mod file building

src/modfile.js

@@ -2,6 +2,8 @@
 
 
 /**
+ * Represents an entire module.
+ * Loads all relevant data into memory, or can be be used to build a new module (TODO)
  * 
  * @param {ArrayBuffer} mod Data to populate this mod with. If not supplied, create an empty mod.
  */
@@ -126,6 +128,20 @@ ModFile.prototype.loadFromData = function(mod) {
 	}
 }
 
+// Stubs for future "create mod" functionality
+
+/**
+ * Return a valid .mod file as an ArrayBuffer
+ */
+ModFile.prototype.createFile = function() {
+}
+
+/**
+ * TODO: Create separate ModSample class. Modify loading code to use it as well as addSample()
+ */
+ModFile.prototype.addSample = function() {
+}
+
 ModFile.channelCountByIdentifier = {
 	'TDZ1': 1, '1CHN': 1, 'TDZ2': 2, '2CHN': 2, 'TDZ3': 3, '3CHN': 3,
 	'M.K.': 4, 'FLT4': 4, 'M!K!': 4, '4CHN': 4, 'TDZ4': 4, '5CHN': 5, 'TDZ5': 5,