gettext: unescape \n

Fixes the problem that any msgid with \n in it wouldn't show up translated.
Merge pull request #1214 from Frenzie/master

Some English improvements in evernote.koplugin
Merge pull request #1215 from Frenzie/gettext

gettext: unescape \n
refactoring: reuse IconButton for config menu bar
consider also the screen size when scaling by DPI
default autoscale for IconButton
remove hardcoded footer height of reader menu
Merge pull request #1216 from chrox/auto_scale

auto scale icon button especially for screen with high DPI