Revert "Add text template domain"

This reverts commit 8462172de1a24fa264c5fa542bacfdda711c76dd.

All the text template domain did was cause tower not to collapse
whitespace when extracting strings. However, gettext calls would
collapse whitespace to create the msgid, so then things never
matched and you'd never get localized strings.

I'm reverting this since it doesn't work.
Merge pull request #16 from willkg/revert-text-domain

Revert "Add text template domain"