Add shims for legacy electron APIs

Signed-off-by: Nathan Sobo <nathan@github.com>

src/electron-shims.js

@@ -0,0 +1,7 @@
+const electron = require('electron')
+
+electron.ipcRenderer.sendChannel = function () {
+  const Grim = require('grim')
+  Grim.deprecate('Use `ipcRenderer.send` instead of `ipcRenderer.sendChannel`')
+  return this.send.apply(this, arguments)
+}