Merge remote-tracking branch 'remotes/afaerber/tags/qom-devices-for-peter' into staging

QOM/QTest infrastructure fixes and device conversions

* qom-test extension
* QEMUMachineInitArgs conversion to MachineState
* -machine options turned into /machine properties
* Named GPIO IRQs for devices

# gpg: Signature made Wed 28 May 2014 18:24:04 BST using RSA key ID 3E7E013F
# gpg: Can't check signature: public key not found

* remotes/afaerber/tags/qom-devices-for-peter:
  ssi: Name the CS GPIO
  qdev: Implement named GPIOs
  machine: Make -machine opts properties of MachineState
  tests: Check empty QMP output visitor
  qapi: Avoid output visitor crashing if it encounters a NULL value
  vl.c: Do not set 'type' property in obj_set_property()
  machine: Conversion of QEMUMachineInitArgs to MachineState
  qom-test: Test qom-list on link<> properties

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>