Use gnutls_priority override for STARTTLS as well.
Free newly created strings from g_markup_printf_escaped

Fixes also build with hardening flags:
• rssyl_update_feed.c:124:6: error: format not a string literal and no
  format arguments [-Werror=format-security]
• rssyl_update_feed.c:135:8: error: format not a string literal and no
  format arguments [-Werror=format-security]
• rssyl_update_feed.c:222:6: error: format not a string literal and no
  format arguments [-Werror=format-security]
RSSyl: start using folder cache
RSSyl: Fix memory leak caused by last commit.
Fix format for translated desktop keywords
RSSyl: Allow use of .netrc by libcurl. Bug/enhancement #3309, by Vincent Pelletier
fix fatal error
Merge branch 'master' of ssh+git://git.claws-mail.org/home/git/claws

Conflicts:
	po/bg.po
remove all traces of intltool, and hence don't install appdata, because it's broken (yes, still!)
add Norwegian Bokmål translation, submiited by Eyolf Østrem
in preparation for release 3.11.1