QOM infrastructure fixes and device conversions

* Changes to name string ownership for alias properties
* Improvements around enum properties
* Cleanups around -object handling
* New helper functions
* Cleanups of qdev init helper functions
* Add path argument to qom-tree script
* QTest cleanup to use new qtest_add_data_func() consistently

# gpg: Signature made Fri Jun 19 18:14:38 2015 BST using RSA key ID 3E7E013F
# gpg: Good signature from "Andreas Färber <afaerber@suse.de>"
# gpg:                 aka "Andreas Färber <afaerber@suse.com>"

* remotes/afaerber/tags/qom-devices-for-peter:
  qdev: Un-deprecate qdev_init_nofail()
  qdev: Deprecated qdev_init() is finally unused, drop
  qom: Don't pass string table to object_get_enum() function
  qom: Add an object_property_add_enum() helper function
  qom: Make enum string tables const-correct
  qom: Add object_new_with_props() / object_new_withpropv() helpers
  qom: Add helper function for getting user objects root
  vl: Create (most) objects before creating chardev backends
  doc: Document user creatable object types in help text
  backends: Fix typename of 'policy' enum property in hostmem obj
  scripts: Add support for path as argument of qom-tree
  tests: Use qtest_add_data_func() consistently
  qdev: Free property names after registering gpio aliases
  qom: strdup() target property name on object_property_add_alias()
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>