Use libmutter-wm, and build a real gnome-shell binary

Build gnome-shell as a binary linked against libmutter-wm, instead of
a module to be loaded by libmutter-wm. Move the majority of
initialization-type stuff from gnome_shell_plugin_start() into main().

We still build libgnome-shell as a shared library, so that the linker
doesn't discard all the methods that are never called from C.

https://bugzilla.gnome.org/show_bug.cgi?id=641724

tests/Makefile.am

@@ -27,7 +27,7 @@ EXTRA_DIST += $(TEST_MISC)
 
 run-test.sh: run-test.sh.in
 	$(AM_V_GEN) sed \
-	    -e "s|@MUTTER_LIB_DIR[@]|$(MUTTER_LIB_DIR)|" \
+	    -e "s|@MUTTER_TYPELIB_DIR[@]|$(MUTTER_TYPELIB_DIR)|" \
 	    -e "s|@srcdir[@]|$(srcdir)|" \
 	    $< > $@ && chmod a+x $@
 

tests/run-test.sh.in

@@ -30,7 +30,7 @@ builddir=`cd $builddir && pwd`
 srcdir=$builddir/@srcdir@
 srcdir=`cd $srcdir && pwd`
 
-GI_TYPELIB_PATH="@MUTTER_LIB_DIR@/mutter:$builddir/../src"
+GI_TYPELIB_PATH="@MUTTER_TYPELIB_DIR@:$builddir/../src"
 GJS_PATH="$srcdir:$srcdir/../js"
 GJS_DEBUG_OUTPUT=stderr
 $verbose || GJS_DEBUG_TOPICS="JS ERROR;JS LOG"