Add translation for test msg/sms

Add translation for test msg/sms, remove dublicate for Smsit gw and small changes in sms text message.
Update bg_BG.lang.php
Update bg_BG.lang.php
Update bg_BG.lang.php
Fixed some grammatical errors.

Fixed some grammatical errors.
Fixed some grammatical errors.
Merge pull request #88 from PVasileff/patch-8

Add BG translation for test msg/sms