Replace http:// with https:// where applicable

The testcases will be updated automatically in a separate commit.

testcases/lib/StartXServer.pm

@@ -57,7 +57,7 @@ sub wait_for_x {
 =head2 start_xserver($parallel)
 
 Starts C<$parallel> (or number of cores * 2 if undef) Xephyr processes (see
-http://www.freedesktop.org/wiki/Software/Xephyr/) and returns two arrayrefs: a
+https://www.freedesktop.org/wiki/Software/Xephyr/) and returns two arrayrefs: a
 list of X11 display numbers to the Xephyr processes and a list of PIDs of the
 processes.
 

testcases/lib/StatusLine.pm

@@ -17,7 +17,7 @@ my $tests_total;
 
 sub noninteractive {
     # CONTINUOUS_INTEGRATION gets set when running under Travis, see
-    # http://docs.travis-ci.com/user/ci-environment/ and
+    # https://docs.travis-ci.com/user/ci-environment/ and
     # https://github.com/travis-ci/travis-ci/issues/1337
     return (! -t STDOUT) || (
         defined($ENV{CONTINUOUS_INTEGRATION}) &&

testcases/lib/i3test.pm.in

@@ -77,7 +77,7 @@ i3test automatically "use"s C<Test::More>, C<Data::Dumper>, C<AnyEvent::I3>,
 C<Time::HiRes>’s C<sleep> and C<i3test::Test> so that all of them are available
 to you in your testcase.
 
-See also C<i3test::Test> (L<http://build.i3wm.org/docs/lib-i3test-test.html>)
+See also C<i3test::Test> (L<https://build.i3wm.org/docs/lib-i3test-test.html>)
 which provides additional test instructions (like C<ok> or C<is>).
 
 =cut
@@ -659,7 +659,7 @@ processes, only after all other events are done.
 This can be used to ensure the results of a cmd 'focus left' are pushed to
 X11 and that C<< $x->input_focus >> returns the correct value afterwards.
 
-See also L<http://build.i3wm.org/docs/testsuite.html> for a longer explanation.
+See also L<https://build.i3wm.org/docs/testsuite.html> for a longer explanation.
 
   my $window = open_window;
   $window->add_hint('urgency');

testcases/lib/i3test/XTEST.pm

@@ -97,7 +97,7 @@ bool inlinec_connect() {
 bool set_xkb_group(int group) {
     xcb_generic_error_t *err = NULL;
     // Needs libxcb ≥ 1.11 so that we have the following bug fix:
-    // http://cgit.freedesktop.org/xcb/proto/commit/src/xkb.xml?id=8d7ee5b6ba4cf343f7df70372a3e1f85b82aeed7
+    // https://cgit.freedesktop.org/xcb/proto/commit/src/xkb.xml?id=8d7ee5b6ba4cf343f7df70372a3e1f85b82aeed7
     xcb_void_cookie_t cookie = xcb_xkb_latch_lock_state_checked(
         conn,
         XCB_XKB_ID_USE_CORE_KBD, /* deviceSpec */