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/gnutls/package.py

@@ -25,7 +25,7 @@
 from spack import *
 
 
-class Gnutls(Package):
+class Gnutls(AutotoolsPackage):
     """GnuTLS is a secure communications library implementing the SSL,
        TLS and DTLS protocols and technologies around them. It
        provides a simple C language application programming interface
@@ -40,8 +40,3 @@ class Gnutls(Package):
     version('3.3.9', 'ff61b77e39d09f1140ab5a9cf52c58b6')
 
     depends_on("nettle")
-
-    def install(self, spec, prefix):
-        configure("--prefix=%s" % prefix)
-        make()
-        make("install")