incorporated vcard-export patch

from here:
https://github.com/webos-internals/patches/blob/webos-2.2.4/contacts/contacts-enhanced-contacts-vcard-export.patch
Those patches are released under a MIT license.
It fixes an issue with URL field and adds relations to export.
added escaping to VCardExporter

according to RFC6350 all values have to escape
COMMA, SEMICOLON, BACKSLACH and NEWLINE.

So I added that to all values.
imporved unescaping in VCardImporter

according to RFC6350 all values have to escape
COMMA, SEMICOLON, BACKSLACH and NEWLINE.

So I added that to all values where it was missing.

Signed-off-by: Achim Königs <garfonso@tratschtante.de>