Escaped possible XML to prevent code injection.

Resolves issue #38.

Theoretically, I could examine each variable and attempt to prove
whether I can guarantee that it is unable to have code injected into
it. Then I would not need to wrap it with the JSTL function `escapeXml`.

On the other hand, I could just escape everything.

I’ll escape everything because `clever laziness === security` in this
case.