skin: Remove pointless assignment

Fixes #2054
Change severity of "Widget XYZ does not respond to attribute" to DEBUG

refs #2055
prop: Only log 'Refusing to clean prop ...' message when PROP_DEBUG is set

Fixes #2053
glw: Trig UI refresh when scrollbar moves

Fixes #2057
glw: Fix recent regression causing empty label/text not to be cleared correctly

Fixes #2056
rpi: Control video display region from GLW instead of letting VideoCore position it by itself

Fixes invalid aspect ratios, also makes video settings (zoom, stretch, etc) work as it should on rpi

Fixes #2030
glw/linux: Add support for conditional UI rendering
rpi: Add option to use CEC Play button as modifier

Fixes #2045
playqueue: Remove a bunch of prop_create() in favour of prop_set()
filebackend: Set page.loading during initial stat/probe of file

Fixes #2050
subtitles: Add support for absolute positioning and fontsize changes in ass/ssa

Fixes #1581
rpi: Remap some CEC keys

Fixes #2059
http: Remove the index.html parser that will parse HTML as directory scan

It was buggy and the use case is somewhat limited / doubtful

Fixes #1945
Fixes #2061
Fixes #2062
Fix broken JPEG file detection

Fixes #2063
rpi: Fix recent regression with video aspect ratio
text: Fix problem with right aligned text spanning multiple lines

refs #2060
Fix various bugs related to font loading and improve glyph caching

refs #2060