The colspan for the "platform type" header cells is initially wrong

[afmenez]

The colspan for the "platform type" header cells is initially wrong. It is corrected dynamically later by setColSpans() on master.js, but since this is the first row, it defines the initial width for the entire table and I believe older browsers can't handle this (see #1127).

One solution is instead of hard-coding the platform headers on skeleton.html, adding them dynamically like the browser headers in dataToHtml() on build.js.