Adding waveTop/waveBottom defaults

THEMES.md

 
 By default, Audiogram will already have access to fonts on your system.  This might be fine for local use, but it will become a problem on a server without the fonts you're used to, or if you want to use a specific font across lots of installations.
 
-The good news is that you can load custom fonts directly with the `fonts` list in `settings/index.js`. Each font in the array is an object with `name` (the font family name in `captionFont`) and `file`, the absolute path to the font file.  For example:
+The good news is that you can load custom fonts directly with the `fonts` list in `settings/index.js`. Each font in the array is an object with `family` (the font family name in `captionFont`) and `file`, the absolute path to the font file.  For example:
 
 ```js
 fonts: [
-  { name: "Gotham", file: "/where/to/find/Gotham.ttf" }
+  { family: "Gotham", file: "/where/to/find/Gotham.ttf" }
 ]
 ```
 
 
 ```js
 fonts: [
-  { name: "Gotham", file: "/where/to/find/Gotham-Bold.ttf", weight: "bold" },
-  { name: "Gotham", file: "/where/to/find/Gotham-Italic.ttf", style: "italic" }
+  { family: "Gotham", file: "/where/to/find/Gotham-Bold.ttf", weight: "bold" },
+  { family: "Gotham", file: "/where/to/find/Gotham-Italic.ttf", style: "italic" }
 ]
 ```
 

renderer/index.js

     options.backgroundColor = options.backgroundColor || "#fff";
     options.waveColor = options.waveColor || options.foregroundColor || "#000";
     options.captionColor = options.captionColor || options.foregroundColor || "#000";
+    if (typeof options.waveTop !== "number") {
+      options.waveTop = 0;
+    }
+    if (typeof options.waveBottom !== "number") {
+      options.waveBottom = options.height;
+    }
     this.wrapText = textWrapper(context, options);
     this.options = options;
     this.waveform = options.waveform || [sample.slice(0, options.samplesPerFrame)];