mtk: Add new atoms

Add atoms that have already been added to ril plugins: call barring,
radio settings and another GPRS context for MMS.
mtkmodem: Fix double registration to voicecall

mtk modem was registering twice to the voicecall atom: once in
rilmodem voicecall driver and once in mtkmodem voicecall driver.
mtk: Fix devinfo on boot

Serial (IMEI) and Revision modem properties were not shown when
re-starting the phone, as the devinfo atom was created when the radio
state was still unavailable.
Merge pull request #82 from alfonsosanchezbeato/mtk-update

Mtk update
gril: Fix parsing of replies for infineon modem

Adjustments to parsing code are needed to handle some request replies
from infineon modem.
unit: Tests for infineon ril modem

Specific tests for some infineon replies.
rilmodem: Support for UCS-2 in USSD

Support to send and receive USSD strings that cannot be codified using
the GSM alphabet.
plugins: fix android-provision crash

Fix a crash in provision_get_settings() caused by the code
freeing 'error' with g_error_free() but not setting the value
to NULL afterwards.  This can cause a subsequent call to
g_error_free() to happen again with an invalid pointer value.
Merge pull request #81 from alfonsosanchezbeato/infineon

Fix parsing of replies for infineon modem
src: Support to send UCS-2 codified USSD strings

Core ofono always codified USSD strings using plain GSM alphabet.
This change uses UCS-2 in case GSM alphabet is not enough.
Merge pull request #84 from tonyespy/fix-provision-crash

Approved.
Merge pull request #83 from alfonsosanchezbeato/ussd-ucs2

USSD - UCS-2
src: Use EF_OPL to check roaming status

Some operators (MVNOs, or Orange/T_Mobile UK case) store in EF_OPL
their home networks, so we remove the roaming flag if the network we
are registered in is present in the file. Although this is not strictly
conformant with the standard, seems to be common practive among
operators, as no operator would care about changing the displayed name
for a network which is not among its home networks (EF_OPL stores the
index for the EF_PNN entry for a PLMN).
test: Adapt test scripts to multi-sim scenarios

Some tests scripts were not ready to handle situations with more than
one modem present. This changes fixes some of the scripts, including
those used in the test plan.
Merge pull request #88 from alfonsosanchezbeato/test-multisim

Adapt test scripts to multi-sim scenarios
Merge pull request #86 from alfonsosanchezbeato/roaming-opl

Use EF_OPL to check roaming status
rilmodem: Fix memory leak
plugins: Fix memory leaks

In the case of ril plugin, the leak is due to devinfo atom being
created before the modem is powered. In that case, ofono core does
not clean up the atom when terminating.
Merge pull request #90 from alfonsosanchezbeato/fix-leaks

Fix memory leaks
gril: Add screen state request

This request informs ril of the current screen state.