Update some rows in Latvian locale

Removed innerHTML from c-intro as it was causing artifacts when changing locales
That is due to fact that webL10n only swaps TEXT_NODE contents (see https://github.com/fabi1cazenave/webL10n/blob/master/l10n.js#L904)

Signed-off-by: Aleksandrs Ļedovskis <aleksandrs@ledovskis.lv>
Translate js-firebug-extra string for ru-RU locale

Signed-off-by: Aleksandrs Ļedovskis <aleksandrs@ledovskis.lv>
Update zh-TW strings

Updating lang-selection and js-firebug-extra
Merge pull request #126 from petercpg/patch-1

Update zh-TW strings
Merge pull request #123 from aledovsky/chore/lv_translation_nits

Update some rows in Latvian locale
Merge pull request #124 from aledovsky/chore/ru-RU_translation_update

Translate js-firebug-extra string for ru-RU locale