fix automake errors

src/plugins/fetchinfo/Makefile.am:83: warning: EXTRA_DIST multiply defined in condition TRUE ...
src/plugins/fetchinfo/Makefile.am:8: ... 'EXTRA_DIST' previously defined here
src/plugins/perl/Makefile.am:38: warning: EXTRA_DIST multiply defined in condition TRUE ...
src/plugins/perl/Makefile.am:8: ... 'EXTRA_DIST' previously defined here
src/plugins/pgpinline/Makefile.am:7: warning: appdata_DATA multiply defined in condition TRUE ...
src/plugins/pgpinline/Makefile.am:5: ... 'appdata_DATA' previously defined here
src/plugins/spamassassin/Makefile.am:42: warning: EXTRA_DIST multiply defined in condition TRUE ...
src/plugins/spamassassin/Makefile.am:8: ... 'EXTRA_DIST' previously defined here

Signed-off-by: Igor Gnatenko <i.gnatenko.brain@gmail.com>
i18n: improve translations

Signed-off-by: Igor Gnatenko <i.gnatenko.brain@gmail.com>
use our own address as <updatecontact>
keep this listing in alphabetical order
Merge branch 'i18n' of https://github.com/ignatenkobrain/claws
Start translating .desktop and .appdata to test new system
Unmark some warnings from translations
Mention intltool
add a check and warning for missing intltool; add --automake to intltoolize call
internationalise plugin appdata files