Move charset to precede <title>.

As referred to in the documentation for h5bp[1], charset should be
defined before <title>. I think the security issue does not apply to the
current form of our project but if we would later dynamically change the
title to match a local language, for example, we might create a
vulnerability. Or perhaps we will create a very long title in the future
so that charset would be pushed beyond the limit of 1024 bytes. ;)

[1] https://github.com/h5bp/mobile-boilerplate/blob/v4.1.0/doc/html.md#the-order-of-meta-tags-and-title