fsogsmd: dump SMS timestamp as string
fsogsmd: dump SMS timestamp as string

...to be consistent with the rest of FSO GSM api - e.g. with
IncomingTextMessage event or RetrieveTextMessages()

slyon/debian-fso-usaged,slyon/debian-fso-deviced,slyon/debian-fso-usaged,slyon/debian-fso-deviced