Code comments and consistency improvements. (#12)

src/main.cpp

@@ -4,9 +4,9 @@
 
 #include <cstdio>
 #include <iostream>
-#include "conf.h"
-#include "crypto.h"
-#include "usr/usr.h"
+#include "conf.hpp"
+#include "crypto.hpp"
+#include "usr/usr.hpp"
 
 using namespace std;
 
@@ -82,5 +82,5 @@ int parse_cmd(int argc, char **argv)
     cout << "hpcore <command> <contract dir> (command = run | new | rekey)\n";
     cout << "Example: hpcore run ~/mycontract\n";
 
-    return 0;
+    return -1;
 }