doc: Add ModemTechnologies property

This new property in org.ofono.RadioSettings interface will hold the
possible values for radio access technology for the modem.
include: Add method to list RATs to radio-settings
src: Implement RAT list property
rilmodem: Implement RAT list query
mtkmodem: Add parser for 3g capabilities reply

Add parser for the reply to a MTK request that queries the 3G
capabilities of the modem.
build: Compile mtkreply.c
unit: Test 3g capability reply parser
gril: Add slot member

This member is needed by parcel parsers in some cases.
mtkmodem: Add RAT list query
ril: Change atom order creation

This change is needed so RadioSettings interface appears also when there
is no SIM, so FastDormancy and other properties are available when
online.
mtk: Change atom order creation

This change is needed so RadioSettings interface appears also when there
is no SIM, so FastDormancy and other properties are available when
online. Additionally, SIM slot is set in gril object.
test: Add ModemTechnologies to list-modems
Merge pull request #103 from alfonsosanchezbeato/avail-rat-list

List valid modem technologies in RadioSettings interface
mtkmodem: Add defines for all MTK specific events

Add defines and change request names to show that they are specific to
MTK.
gril: Delete marked callbacks

Callbacks were not being removed if unregistration was happening inside
a callback call, they were just being marked. This change makes sure
that marked callbacks are deleted after handling the event that
started the callback that marked them.
mtk: Handle SIM hot swap

This change re-starts atoms after detection of SIM insertion/removal
for MTK modem.
unit: Adapt tests to MTK events name change