RTL layout bugs.

[chrisgarrity]

Expected Behavior

Styles that are asymmetric on the gui should mirror when in Hebrew or any RTL language.

Actual Behavior

Steps to Reproduce

Switch into Hebrew

[cyx2015s]

I found more

[Kenny2github]

Corners not rounded: change border-radius: 0 xpx xpx 0 to border-radius: xpx 0 0 xpx when switched.
Border missing from blocks palette: change border-right: ... to border-left: ... when switched.
Language menu misaligned: ...I don't really know.
Dropdown buttons in paint editor are rounded wrong: same fix as stage corners.

[chrisgarrity]

@Kenny2github @cyx2015s thanks for these additional layout problems - just one note, all the paint editor bugs are getting tracked in a separate issue: scratchfoundation/scratch-paint#574

[carljbowman]

Another place where we use absolute positioning: 'Coming Soon...' tag on extension tiles

Inline icons usually only have margin-right to space icons from the text:
Example from the "Create a variable" modal

[chrisgarrity]

Mirror small/large stage icons:

Don't mirror sound and paintbrush: