Add catches_strings test to test throws char * typemap

Examples/test-suite/tcl/catches_strings_runme.tcl

@@ -0,0 +1,18 @@
+
+if [ catch { load ./catches_strings[info sharedlibextension] catches_strings} err_msg ] {
+	puts stderr "Could not load shared object:\n$err_msg"
+}
+
+
+set exception_thrown 0
+if [ catch {
+  StringsThrower_charstring
+} e ] {
+  if {[string first "charstring message" $e] == -1} {
+    error "incorrect exception message: $e"
+  }
+  set exception_thrown 1
+}
+if {!$exception_thrown} {
+  error "Should have thrown an exception"
+}