Printing: fix text resolution

Scintilla doesn't respect the context resolution, so we need to scale
its draws ourselves.
Printing: draw the vertical separator line more accurately

Use the dimensions and offsets used by Scintilla to position our
separator line, since its position depends on where Scintilla drawn.

Closes #3580268.
Printing: fix improper margins when printing to a physical device

We were improperly adding the printing device margins to the area
where we print, leading to wider margins on physical outputs than
on PDF or preview outputs (which have no hard margins), as well as
wasting space and not respecting user's settings.

Closes #3580269.
Implement terminal background image
po/et.po: Initial version of estonian translation: 278 translated, 2 fuzzy, 961 not translated
po/et.po: Translation update: 365 translated, 6 fuzzy, 870 untranslated
Merging a first version of Estonian translation
po/et.po: 623 translated, 2 fuzzy, 616 untranslated
po/et.po: 650 translated, 2 fuzzy, 589 untranslated
po/et.po: 650 translated, 2 fuzzy, 589 untranslated
Merge?
po/et.po: Header fix
po/et.po: Git trashed the translations
po/et.po: 970 translated, 4 fuzzy, 267 untranslated
Merge pull request #89 from andreasots/master

Update to Estonian translation
Scintilla: properly update the Pango contexts for the target surface

This fixes drawing on a surface that has different settings (like
scaling) than the display surface, by performing the measurements on a
layout properly set up for the target surface.

In practice, this fixes e.g. printing on a scaled surface.

(Applied to Scintilla HG as 74c71632dd1afa726b0f1608d13413e0864da9b0)
Merge branch 'printing-with-scintilla'
Revert "Alter default and document icon setting"

This reverts commit 306eaab3916649567c892215ad8390b9d39de82f.
Revert "Make use of theme icon a various pref."

A preference for an icon doesn't make sense;  if someone don't like
her theme's icon she should either switch to another theme, override
that specific icon or don't bother.

This reverts commit 6897cd49c69535c6563e56ae011c6f8382fec485.
Use the Geany icon from the theme everywhere