qt currently seems very slow at calculating width of language dropdown,
so we change the setting to delay dropdown appearance instead of
appearance of the dialog
- use a main window instead of a dialog, so the menu items of the main
window don't appear while the profile window is active on OS X
- the profile manager now has a button to automatic restoring from
backup, which will prevent old backups from being clobbered
- drop support for profile passwords
- do the right thing when user quits from the menu in profile manager
mode
we do the backup compression/writing in a separate thread so it
doesn't slow down profile switching/syncing, and remove the option
to write uncompressed backups
the strip html option is no longer used, so remove it from preferences
avoided adding this in the past as on a multi user system it allows
one profile user to annoys others by changing the interface language,
but it comes at the expense of easily changing the language for users
who choose the wrong one on first startup
