src/sage/features: Add more all_features functions

src/sage/features/dvipng.py

@@ -34,3 +34,7 @@ def __init__(self):
         """
         Executable.__init__(self, "dvipng", executable="dvipng",
                             url="https://savannah.nongnu.org/projects/dvipng/")
+
+
+def all_features():
+    return [dvipng()]

src/sage/features/ffmpeg.py

@@ -37,5 +37,5 @@ def __init__(self):
                             url="https://www.ffmpeg.org/")
 
 
-def all_packages():
+def all_features():
     return [FFmpeg()]

src/sage/features/pdf2svg.py

@@ -35,3 +35,7 @@ def __init__(self):
         Executable.__init__(self, "pdf2svg", executable="pdf2svg",
                             spkg='pdf2svg',
                             url="http://www.cityinthesky.co.uk/opensource/pdf2svg/")
+
+
+def all_features():
+    return [pdf2svg()]