DVBSub: Properly handle page update

Fixes the case when previous regions were removed from the screen while
they should not.
ISR: Crop PGS and DVB subtitles if they don't fit.

- Preserve aspect ratio of subtitle frame
- Crop subtitle frame if it's bigger than video frame in order to correctly display subtitles when video frame was cropped.
BVF: Pass through colorimetry information

This enables the usage of colorimetry information passed down the
filter chain from the decoder.

Currently limited to a white list of filters:
 - VMR7,9
 - EVR
 - madVR
ISR/VSFilter: Use correct colorimetry information for PGS and DVB subtitles.

- Fix YCbCr to RGB conversion methods. 255.0 / 112.0 is not equal 2!
- Use correct values for BT.709 conversion.
DVB: Don't update stats when channel is not active.
DVB: Show current event time in the status bar
DVB: Make use out of the DVBState struct.
Mpeg2SectionData: Minor refactioring of the ParseEIT() method
DVB: Cosmetic for SetChannel()
Cosmetics for timers.
Cosmetics for stats.
DVB: Fix time calculations

StartTime was day off in certain cases.
DVB: Add channel name to snapshot filename
DVB: Add only supported services.
DVB: Add context menu to navigation dialog.

Use std::vector to store channel in order to get better sort abilities.