Fix for wrongly sized live preview in guide

[<celston AT katalix D com>]

I noticed that If I had a letterbox format setting other than "Off", and then went into the guide - that the live video preview wouldn't always stay contained within the range specified in the theme ("current_video" field in ui.xml). For example, if I have the letterbox set to wide, and then go into the guide, the current_video displayis wider than the size specified and obscures some of the surrounding theme.

The attached patch turns any letterbox setting in the embedded NVP off when we go into the guide, and then returns it to the previous setting once we exit the guide. The usual OSD message giving the new letterbox setting is inhibited because the user shouldn't need to know.

Notes:

• Exposes the existing TV::ToggleLetterbox? function as public (which used to be private) - this may or may not be a bad thing - opinions?
  
• It adds a new public function TV::ToggleLetterbox?(int, bool), where the second parameter allows us to inhibit the OSD display caused when you change letterbox setting.
  
• It adds a new public function TV::GetLetterbox? to allow the guide grid to get the previous letterbox state.
  

I've CC'd who I think the mythui maintainer is, if I've got it wrong, please let me know :-)

Cheers,

Chris.

[celston AT katalix D com]

Patch to turn letterbox settings to "off" in the guide

[Dibblah]

Does this still apply with MythUI?

[stuartm]

Not even sure it still applies 0.21, let alone once these screens are ported to mythui.