Hastymail plugins support a simple translation method (similar to how Hastymail
hanldes interface translations). To setup string translations for a plugin add
an array to the plugin's config.php file like so:

    $<plugin_name>_langs = array(
        'en_US' => array(
            1 => 'Phrase one',
            2 => 'Phrase two',
            ...
        ),
        'es_ES' => array(
        ),
        ...
    );

The plugin system will store this array on login and if a section exists that
matches the users currently selected language it will be used. Otherwise the default
site language will be used if it is found. If that is not present than the first
entry in the array will be used (en_US in this case). Interface strings are made
available to a plugin through the tools object. Using the above example a
translated string can be used in the display.php and page.php files of a plugin
by replacing this:

    $data = 'Phrase one';

with this:

    $data = $tools->str[1];


To add a translation just copy the default set of
strings, change the name to one of the supported languages, and translate
each string accordingly. As of this writing the language names supported by
Hastymail are:

bg_BG Bulgarian
ca_ES Catalan
zh_CN Chinese
nl_NL Dutch
en_US English
fi_FI Finnish
fr_FR French
de_DE German
gr_GR Greek
it_IT Italian
ja_JP Japanese
pl_PL Polish
ro_RO Romanian
ru_RU Russian
es_ES Spanish
tr_TR Turkish
uk_UA Ukranian


- The array of strings is only read when logging in, so existing logins
  have to logout and back in before seeing the new strings.
- Both the hello_world and filters plugins are now setup to use this
  system so see the plugin code for examples.
