Massive conversion from Package to AutotoolsPackage (#2845)

* Massive conversion from Package to AutotoolsPackage

* Forgot to convert p4est to AutotoolsPackage

* Fix typo

* Fix broken link in docs

var/spack/repos/builtin/packages/libmng/package.py

@@ -25,7 +25,7 @@
 from spack import *
 
 
-class Libmng(Package):
+class Libmng(AutotoolsPackage):
     """libmng -THE reference library for reading, displaying, writing
        and examining Multiple-Image Network Graphics.  MNG is the animation
        extension to the popular PNG image-format."""
@@ -42,8 +42,3 @@ def patch(self):
         # jpeg requires stdio to beincluded before its headrs.
         filter_file(r'^(\#include \<jpeglib\.h\>)',
                     '#include<stdio.h>\n\\1', 'libmng_types.h')
-
-    def install(self, spec, prefix):
-        configure("--prefix=%s" % prefix)
-        make()
-        make("install")