[REVIEW][3-5] fdo#33634, fdo#49438 border line drawing regressions

[Michael Stahl]

drawing of borders in Calc looks rather ugly, the lines suddenly getting
much fatter when zooming in etc., and there's a fix for that by moggi,
mostly doing arithmetic on doubles and changing the hairline predicate
from something that is right for Writer to something that is right (or
at least not as wrong) for Calc:

http://cgit.freedesktop.org/libreoffice/core/commit/?id=2c91cb08d65cd35fa8ef6eaca3677aa82fb58cbe

this fix unfortunately introduces a regression that thin lines become
invisible when anti-aliasing is disabled, and i've come up with this
horrible hack that seems to fix it for me:

http://cgit.freedesktop.org/libreoffice/core/commit/?id=ee42895d684be9430a414adf3f569d279d437148

so i'd say we should backport both of these to libreoffice-3-5.