Fixed == operator for empty string comparison.

testing/compile

@@ -1,4 +1,4 @@
 #!/bin/bash
-g++ -o zstring_test zstring_test.cpp -I.. -L.. -lCoreUtils
-g++ -o mstring_test mstring_test.cpp -I.. -L.. -lCoreUtils
+g++ -g -o zstring_test zstring_test.cpp -I.. -L.. -lCoreUtils
+g++ -g -o mstring_test mstring_test.cpp -I.. -L.. -lCoreUtils
 #g++ -o jstring_test jstring_test.cpp -I.. -L.. -lCoreUtils

testing/zstring_test.cpp

@@ -6,8 +6,9 @@ int main(int argc, char **argv) {
 
    // Test comparison operations.
 
-   coreutils::ZString test1("");
+   coreutils::ZString test1("else");
    std::cout << (test1 != ".") << std::endl;
+   std::cout << (test1 == "") << std::endl;
 
    // Test constructors.