Work in progress. Move font scaling based on safe area to SubtitleFormat.

SubtitleFormat now needs access to SubtitleScreen for safe area,
and MythPlayer for aspect ratio.

Make sure teletext captions benefit from better font scaling.

Cache fonts to reduce work done in SubtitleFormat::GetFont.
Had to eliminate const keyword from Calc methods as side effect.

Account for shadow offsets and outline sizes.
Fix scaling for theme to screen of both.

Fix memory leak in SubtitleFormat::CreateProviderDefault.

608 captions should be done.

See https://code.mythtv.org/trac/ticket/12057
Get rid of pixelSize arg from SubtitleFormat::GetFont

Also makes m_fontSize and SetFontSize members of SubtitleScreen obsolete.
Missed some CC708CharacterAttribute members in SubtitleFontKey.

Especially actual_fg_color.
I think I've got it!

Fix core dump associated with teletext captions.

Fix 708 and text captions being shifted 1/2 char width to left.
FormattedTextLine::CalcSize can be told to exclude padding.
This could affect the SubShape created in FormattedTextSubtitle708::Draw
if it ever IS created, because it uses the m_mbounds
that no longer includes padding.

Changed LINE_SPACING to 0, disabling the feature.

Commented out PAD_HEIGHT which is no longer used.

The biggie: Center 708 window addressable area based on font metrics.

Fix "Intersected bounds" debug logging.
Add padding to m_bounds.
Reverse a change to intersected bounds I shouldn't have made.
Set stretch factor in SubtitleFormat::Load
Pad for italics.
Cleanup formatting, comments, and "git diff" results.
Cleanup formatting. Fix log msg.
Represents patch sent to Jim.
Make sure captions are drawn after new ones are added.

Don't just depend on bounding rectangle changes.