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/gtkplus/package.py

@@ -25,7 +25,7 @@
 from spack import *
 
 
-class Gtkplus(Package):
+class Gtkplus(AutotoolsPackage):
     """The GTK+ 2 package contains libraries used for creating graphical user
        interfaces for applications."""
     homepage = "http://www.gtk.org"
@@ -47,8 +47,3 @@ def patch(self):
         # remove disable deprecated flag.
         filter_file(r'CFLAGS="-DGDK_PIXBUF_DISABLE_DEPRECATED $CFLAGS"',
                     '', 'configure', string=True)
-
-    def install(self, spec, prefix):
-        configure("--prefix=%s" % prefix)
-        make()
-        make("install")