Testing using libvips8.4.6 from Github.

As of today, the libvips website is down.

Signed-off-by: Yoan Blanc <yoan@dosimple.ch>

.travis.yml

@@ -13,7 +13,7 @@ env:
   - LIBVIPS=7.42.3
   - LIBVIPS=8.2.3
   - LIBVIPS=8.3.3
-  - LIBVIPS=8.4.5
+  - LIBVIPS=8.4.6
   - LIBVIPS=8.5.6
   - LIBVIPS=master
 
@@ -48,11 +48,11 @@ addons:
 # VIPS 8.3.3 requires Poppler 0.30 which is not released on Trusty.
 before_install:
   - >
-    test "$LIBVIPS" != "master" -a "$LIBVIPS" \< "8.5" \
+    test "$LIBVIPS" != "master" -a "$LIBVIPS" \< "8.4" \
         && wget http://www.vips.ecs.soton.ac.uk/supported/${LIBVIPS%.*}/vips-${LIBVIPS}.tar.gz -O vips.tgz \
         || echo ":-)"
   - >
-    test "$LIBVIPS" != "master" -a "$LIBVIPS" \> "8.5" \
+    test "$LIBVIPS" != "master" -a "$LIBVIPS" \> "8.4" \
         && wget https://github.com/jcupitt/libvips/releases/download/v${LIBVIPS}/vips-${LIBVIPS}.tar.gz -O vips.tgz \
         || echo ":-)"
   - >