Update error.php

Changes start at line 154.
This gets the main menu displaying correctly but does not fix two other things:
sticky footer (I don't know why the CSS is not applied)
loading of a module within another module. (Tried loadmodule and loadposition to no avail; perhaps because I am using a custom html module for the footer ... the module class is not picked up either.)
As well, I have not figured out how to make the button work for displaying the menu in tablet view.

You can see my custom application here: http://silverplains.ca/floa.html
Wouldn't we also want the hamburger icon (https://github.com/construct-framework/bootstruct/blob/develop/index.php#L64-68) here as well?