GUI.OnScreensaverDeactivated does not follow JSON-RPC API definition

The announcement of `GUI.OnScreensaverDeactivated` does not follow the
defined API - it outputs `data` as a `boolean`, not `null`.  This
behaviour was introduced in ea9f2f01 to support a special case for CEC
devices, that must choose to act based on whether this notification was
triggered on the back of a shutdown.

As the rest of the API defines `data` to be of type `null` or `object`,
I've moved this boolean to a `shuttingDown` member on the data object,
rather than changing the API to be inconsistent for a special case.
Bump json-rpc schema version
[ios8] - fix orientation bugs when compiling against ios 8.0 SDK (seems apple fixed
the 90 degree rotated display orientation since 8.0) - thx to mikrohard
[ios8] - fix external screen orientation on ios8 runtime when compiling with ios8 sdk
[ios8] - fix invisible textfield on native keyboard
[ios8] - fix crash in vtb when seeking (changed flag for dropping frames since ios8 runtime)
Merge pull request #5477 from Memphiz/ios8fixups

[ios8] - bugfixes for ios8 runtime
Merge pull request #4661 from pdf/fix_OnScreensaverDeactivated_API

json-rpc: GUI.OnScreensaverDeactivated does not follow JSON-RPC API definition
json-rpc: add possibility to force using the default player through Player.Open
Merge pull request #5454 from Montellese/jsonrpc_player_open_default

json-rpc: add possibility to force using the default player through Player.Open