Makes gtest compile cleanly with MSVC's /W4 (by Zhanyong Wan).

Renames EventListenrs to TestEventListeners (by Zhanyong Wan).
Fixes invalid characters in XML report (by Vlad Losev).
Refacotrs SConscript (by Vlad Losev).

include/gtest/internal/gtest-internal.h

@@ -745,9 +745,15 @@ class TypeParameterizedTestCase<Fixture, Templates0, Types> {
 // the trace but Bar() and GetCurrentOsStackTraceExceptTop() won't.
 String GetCurrentOsStackTraceExceptTop(UnitTest* unit_test, int skip_count);
 
-// A helper for suppressing warnings on unreachable code in some macros.
+// Helpers for suppressing warnings on unreachable code or constant
+// condition.
+
+// Always returns true.
 bool AlwaysTrue();
 
+// Always returns false.
+inline bool AlwaysFalse() { return !AlwaysTrue(); }
+
 // A simple Linear Congruential Generator for generating random
 // numbers with a uniform distribution.  Unlike rand() and srand(), it
 // doesn't use global state (and therefore can't interfere with user
@@ -854,7 +860,7 @@ class Random {
 
 #define GTEST_TEST_BOOLEAN_(boolexpr, booltext, actual, expected, fail) \
   GTEST_AMBIGUOUS_ELSE_BLOCKER_ \
-  if (boolexpr) \
+  if (::testing::internal::IsTrue(boolexpr)) \
     ; \
   else \
     fail("Value of: " booltext "\n  Actual: " #actual "\nExpected: " #expected)