tests/tweet_length: Fix https-link function pointer
tests/inlinemediadownloader: Test wrong url
tests/makefile.am: fix test name aligning
Settings: Small code style fix
configure.ac: Don't forget --vapidir parameter for valac
configure.ac: Fix vapidir path
InlineMediaDownloader: Fix callbacks

Found "thanks" to our great unit tests. There go like 16 hours of my
life.
tests/inlinemedia: Add test cases for inline media downloading