Fix a vulnerability in password encryption

* There was an error in the encryption used to save passwords,
  now it's really harder to decrypt the password from the config file
* Other minor changes

src/framework/core/resourcemanager.cpp

@@ -68,7 +68,7 @@ bool ResourceManager::discoverWorkDir(const std::string& existentFile)
 
 bool ResourceManager::setupUserWriteDir(const std::string& appWriteDirName)
 {
-    std::string userDir = PHYSFS_getUserDir();
+    std::string userDir = getUserDir();
     std::string dirName;
 #ifndef WIN32
     dirName = stdext::format(".%s", appWriteDirName);
@@ -306,6 +306,11 @@ std::string ResourceManager::getBaseDir()
     return PHYSFS_getBaseDir();
 }
 
+std::string ResourceManager::getUserDir()
+{
+    return PHYSFS_getUserDir();
+}
+
 std::string ResourceManager::guessFileType(const std::string& filename, const std::string& type)
 {
     if(g_resources.fileExists(filename))

src/framework/core/resourcemanager.h

@@ -66,6 +66,7 @@ public:
     std::string getRealDir(const std::string& path);
     std::string getCurrentDir();
     std::string getBaseDir();
+    std::string getUserDir();
     std::string getWriteDir() { return m_writeDir; }
     std::string getWorkDir() { return m_workDir; }
     std::deque<std::string> getSearchPaths() { return m_searchPaths; }