Support Simplified and Traditional Chinese scripts.

This fixes the "Command \chinesefont already defined." crashers.

Change-Id: I8bc6662e1ec207cf496f062ee7cc0525bcb66276
Don't crash if images are inside <DT> tags.

This fixes the "! Argument of \Gin@ii has an extra }." crasher.

Change-Id: Ic4cc0644caa2eb29fdec63672cff3c622654fdbd
Fix TeX escaping of [].

`\\ [...] blah` was crashing LaTeX in [[The Minister and the Massacres]]
because the [ was being parsed as the optional argument to the `\\` command.

While we're at it, properly quote " and fix a missing g flag on the
smart single quote rule.

Change-Id: Ifb1ee7f16285ccca6963a66068f2a7df72922520
Fix "There's no line here to end." crasher (<br> after <dd>).

Change-Id: I6a2b45aa54f495f97ad7ab7ea410c23363a82c52
Ensure that we switch to the latin font where necessary.

Initialize the 'latin switch' boolean based on the default collection
language, and use the formatter to emit the title, subtitle, summary,
and chapter titles.

Change-Id: I4b7d5963ba1615c66ab73cd39ccb01651b3cb801
Indic language support.

Add missing polyglossia `gloss-*.ldf` files so that appropriate fonts
are selected for Assamese, Gujarati, Marathi, Oriya, and Punjabi.

(Note that the Marathi gloss corrects a typo in the upstream gloss.)

Change-Id: Iba4b904a738c59cc585a3cd29543d420d8b8c192