Cosmetic: Fix a typo.
CompositionObject: Fix copy-paste fiasco.
Text subtitles: Improve the error message when the parsing fails.

Make the message clearer and display the line that caused the error.

Fixes #4428.
Text subtitles: Lower the priority of SAMI and USF for format detection.

SAMI is costly to rule out and both are quite uncommon.

This makes opening ASS/SSA files about 10% faster.
Text subtitles: Various minor optimizations and cosmetics.

Reorder a conditional for better performance, don't construct empty object to initialize them later, use correct character type...
Text subtitles: Avoid useless conversion from CStringW to CString.

Around 5% faster.
Text subtitles: Optimize GetInt and GetFloat.

Avoid creating empty string objects and useless conversions to lowercase.

Around 5% faster overall on a random test file.
Text subtitles: Optimize white space trimming.

Around 20% faster.
Text subtitles: Prefer wcstol/wcstod to swscanf_s for simple conversions.

wcstol/wcstod are 4 or 5 times faster than swscanf_s when parsing just one number.

Around 10% faster loading overall on my ASS test file.
Text subtitles: Much faster string tokenization.

Avoid reallocating the buffer.

Around 20% faster.
Text subtitles: Tokenize numerical values without string copy.

Around 25% faster parsing.
Subresync bar: Various cosmetics.
Subresync bar: Make the list control virtual for faster loading.

The list control is just a view for the subtitle data so there is no need to duplicate it into the list control.

This makes loading a subtitle into the Subresync bar nearly instant even for complex subtitle files which will now be order of magnitude faster to load.
Accept loading more than one subtitle file at a time using drag-and-drop.
"Load subtitle" dialog: fix the filter and simplify the code.

It was mostly broken for Windows Vista+ but improve the filters while at it.
Add subtitle files to Windows recently opened files only when "keep the history" is enabled.
"Load subtitle" dialog: Allow loading more than one file at a time.
Don't force any background color for the Shockwave graph.

This commit fixes #1747.
ISR: Render text subtitles relative to the video frame when in doubt.
Why "C:\tmp.srt"?