asterisk-chan-dongle:
 * improve support for sending [http://en.wikipedia.org/wiki/Unstructured_Supplementary_Service_Data USSD] commands - inspired by code provided [http://maier.su/topic/making_donglesendussd_for_chan_dongle_in_asterisk/ here], patch prepared by waldoo
 * refs #706


git-svn-id: file:///var/svn/freetz/trunk@12203 149334a1-2f27-0410-a3b9-fc62619ac1e6