ref-manual: Added some more undocumented classes

Paul sent a few more for the list.

(From yocto-docs rev: ea4dd51b4e5fdedf767d8318507551f00c6d46d3)

Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/ref-manual/ref-classes.xml

@@ -981,6 +981,7 @@
         allarch.bbclass
         archive*.bbclass
         binconfig.bbclass
+        bin_package.bbclass
         blacklist.bbclass
         bootimg.bbclass
         boot-directdisk.bbclass
@@ -989,6 +990,7 @@
         buildstats.bbclass
         ccache.bbclass
         chrpath.bbclass
+        clutter.bbclass
         cmake.bbclass
         cml1.bbclass
         copyleft_compliance.bbclass
@@ -998,7 +1000,9 @@
         crosssdk.bbclass
         deploy.bbclass
         distrodata.bbclass
+        distro_features_check.bbclass
         dummy.bbclass
+        extrausers.bbclass
         fontcache.bbclass
         gconf.bbclass
         gettext.bbclass
@@ -1017,12 +1021,11 @@
         image-mklibs.bbclass
         image-prelink.bbclass
         image-swab.bbclass
-        imagetest-dummy.bbclass
-        imagetest-qemu.bbclass
         image_types.bbclass
         image_types_uboot.bbclass
         insserv.bbclass
         kernel-arch.bbclass
+        kernel-module-split.bbclass
         kernel-yocto.bbclass
         lib_package.bbclass
         linux-kernel-base.bbclass
@@ -1063,6 +1066,7 @@
         sip.bbclass
         siteconfig.bbclass
         sourcepkg.bbclass
+        spdx.bbclass
         sstate.bbclass
         staging.bbclass
         syslinux.bbclass
@@ -1071,8 +1075,11 @@
         tinderclient.bbclass
         toolchain-scripts.bbclass
         typecheck.bbclass
+        uboot-config.bbclass
         utility-tasks.bbclass
         utils.bbclass
+        vala.bbclass
+        waf.bbclass
 -->