Initial commit
Add initial umtsd2 sources

These sources are originally written for Fon and taken from the internal
fon-ng2 git repository (rev 12c5885).
Fill README.md a bit
Add GPLv2 full text
Remove unneeded includes.
Include a local version of ucix

Recent libubox versions don't have ucix.h and ucix.c anymore. This version of
ucix is taken from the last libubox version that still had it and was
changed only to include stdlib.h and correct the list.h include.
Include syslog.h where needed

Seems that this one was previous included by libubox or uci but not with
newer versions of these libraries.
Explicitely link against uci

Newer versions of libubox don't link against uci anymore, so this allows
umtsd2 to work with both new and old versions of libubox.
Support older versions of uci which use "history" instead of "delta"
Let umtsd depend on its header files
Include a non-versioned Makefile.local
Fix umtsd -p argument number checking, so it actually works
Do not do AT+GCAP and AT+CREG=2 when running umtsd -u
Add sleep_seconds() function to umtsd2
Let umtsd wait 5 seconds after entering the PIN
Make umtsd2 a bit more verbose in its logging
Let umtsd2 accept OK as well as NOCARRIER

A modem was observed that occasionally replied to a ATD command with OK
instead of (or in addition to) a NOCARRIER reply.
In umtsd -v -v, output raw strings written and read.
Let umtsd -v options propagate to pppd.
Improve (error) logging in umtsd a bit more.