FreeBSD: use "pkg install" instead of "pkg_add -r"

pkg_add was replaced with pkgng.

FreeBSD 10.2 doesn't have pkg_add preinstalled,
while pkg is available.

Some packages were renamed:
  * glib20 is now glib
  * perl is now perl5

Read more: https://lists.freebsd.org/pipermail/freebsd-ports/2012-August/077909.html

index.html

@@ -664,10 +664,10 @@ USE_OSGPLUGIN(<plugin2>)
     <h3 id="requirements-freebsd">FreeBSD</h3>
 
     <!-- http://www.freshports.org/ -->
-    <pre>pkg_add -r \
-    automake autoconf bash bison coreutils flex gdk-pixbuf2 \
-    gettext git glib20 gmake gperf gsed intltool libffi \
-    libtool openssl p5-XML-Parser p7zip patch perl \
+    <pre>pkg install \
+    automake autoconf bash bison coreutils flex \
+    gdk-pixbuf2 gettext git glib gmake gperf gsed intltool libffi \
+    libtool openssl p5-XML-Parser p7zip patch perl5 \
     pkgconf python ruby scons unzip wget</pre>
 
     <p>