switch to googletest as a submodule

wscript

@@ -23,10 +23,10 @@ def build(bld):
         test_libs += ["pthread"]
     test_sources = bld.path.ant_glob("src/core/**/*.cc")
     test_sources += bld.path.ant_glob("test/src/**/*.cc")
-    test_sources += ["gtest-1.7.0/src/gtest-all.cc",
-                     "gtest-1.7.0/src/gtest_main.cc"]
+    test_sources += ["libs/googletest/src/gtest-all.cc",
+                     "libs/googletest/src/gtest_main.cc"]
     test_includes = ["src/core"]
-    test_includes += ["gtest-1.7.0/include", "gtest-1.7.0"]
+    test_includes += ["libs/googletest/include", "libs/googletest"]
     bld(features = "cxx cxxprogram",
         target = "tests",
         source = test_sources,