Review i18nstrings modules for tt() use

In preparation for a stable release, we should do a review of all the modules using i18nstrings.

The idea is to ensure the basics are covered.

That is:

1. tt() is called with the update argument set to TRUE when items are created or updated.

This is generally done by registering submit handlers to forms where the original items are added or edited.

2. i18nstrings_remove_string() is called when items are deleted.

This is generally done by registering a submit handler to a delete confirm form.

3. tt() is called with only the first two arguments (update defaults to FALSE) when items are being prepared for viewing.

4. The 'refresh' op is implemented in hook_locale, providing mass processing of existing items.

Look in hook_locale for the 'refresh' op and how it's handled.

As a sample, I looked at i18nblock module. It appears that the delete functionality isn't there.

Let's create separate issues for each module missing one or more of these pieces, linking to the issues here.