ST: Research adds examples that demos pthread and helloworld. v6.0.118 (#3989)

1. `trunk/research/st/exceptions.cpp` About exceptions with ST, works
well on linux and mac, not work on cygwin.
2. `trunk/research/st/pthreads.cpp` About pthreads with ST, works well
on all platforms.
3. `trunk/research/st/hello.cpp` Hello world, without ST, works well on
all platforms.
4. `trunk/research/st/hello-world.cpp` Hello world, with ST, works well
on all platforms.
5. `trunk/research/st/hello-st.cpp` A very simple version for hello
world with ST, works well on all platforms.

trunk/research/st/hello.cpp

@@ -0,0 +1,11 @@
+/*
+ g++ hello.cpp -g -O0 -o hello && ./hello
+ */
+
+void foo() {
+}
+
+int main(int argc, char** argv) {
+    foo();
+    return 0;
+}