[SS] Fixed bug with empty USSD

Change-Id: I8a6c3e371bb2c87482ad70589e789f41dcb75baa
[SMS] Reworked SMS sending. Fixed bug with multipart SMS

Change-Id: Ie6853ade6f2cf5ffbb78c99da25fd637d7954f3c
Merge pull request #14 from Volk204/experimental

Experimental