Improved alert/error messages and button labels.

Provide a stopgap solution:  route all tor messages captured by
Tor Launcher to the Browser Console.

If Tor Launcher started the tor process and it exits, display
a prompt that allows the user to restart tor.

Use 'make TL_LOGO=- ...' to build without a logo or
    'make TL_LOGO=path.png ...' to substitute a custom logo (115 x 80 pixels).

Update the logo that is displayed in the network settings wizard.

Increase the progress window width slightly and allow for three lines
in the description field.

This is a partial fix (network settings wizard only).
Also fixed a nuisance:  the torWarning CSS class was being added
  more than once to the "Copy Tor Log To Clipboard" button.

Remove 'si' locale files (locale has been removed from Transifex).

The problem has recurred for this file.

Account for new directory structure in getTorFile().
On Windows, prepend the directory that contains tor.exe to PATH.

When starting tor, pass the geoip6 file location (within the tor data dir)
via the GeoIPv6File command line config option.

Remove locales that have been removed from Transifex.

Fixed problem where the Proxy Type menu was not restored to the
configured value after restarting the browser.

This is convenient for `localization/translations` and `pkg`.

Previously chrome.manifest defined locales for pretty much every
existing locale. Many of these were out-of-date (lacking entities,
which results in fatal XUL errors) or completely absent (also fatal).

Instead of maintaining a static list of which locales to register we
generate it programatically, making sure that only those that seem
complete are included. We also make sure to register "en-US" since
it's the hardcoded fallback for unregistered locales. Note that it's
currently called "en" in the Transifex translation repos.

The BUNDLE_LOCALES environment variable can be set to specify a list
of which locales to bundle ("en-US" is always implied). If it's empty
we optimistically try to include all locales. For this reason
import-translations.sh imports all translations from Transifex, and
it's important to run it before packaging since up-to-date
translations are necessary to avoid the issues mentioned above.

Also update translations.