Update wx with fixes for accelerators i18n
Add menu shortcuts to translatable strings

They are from wx, but force their translation in Poedit's PO files for
better coverage.
Better welcome screen icon - match website's

Don't use app icon here, because it's too in-your-face; something more
subtle is better.
Fix terminology: automatic -> extracted comments
Preserve word-wrapping of extracted comments

Keep the newlines as they were in the PO file when displaying extracted
comments in the sidebar.