fix some qualifiers dealing with loadFile()

src/AV.cc

@@ -259,7 +259,7 @@ AV::Sound::~Sound()
     }
 }
 
-bool AV::Sound::load(unsigned char *data, unsigned int size)
+bool AV::Sound::load(const unsigned char *data, unsigned int size)
 {
     m_data = new unsigned char[size];
     memcpy(m_data, data, size);

src/AV.h

@@ -27,7 +27,7 @@ class AV
             public:
                 Sound(AV & av);
                 ~Sound();
-                bool load(unsigned char *data, unsigned int size);
+                bool load(const unsigned char *data, unsigned int size);
                 void play();
                 void resume();
                 void stop();

src/Engine.cc

@@ -636,11 +636,11 @@ int Engine::loadSound(const string & name)
         refptr<AV::Sound> avs = m_av.createSound();
 
         unsigned int size;
-        unsigned char *data = loadFile(nm.c_str(), &size);
+        const unsigned char *data = loadFile(nm.c_str(), &size);
         if (data != NULL)
         {
             bool loaded = avs->load(data, size);
-            free(data);
+            delete[] data;
             if (loaded)
                 return addSound(avs);
         }
@@ -1283,7 +1283,7 @@ const unsigned char *Engine::loadFile(const char *fname, unsigned int *len)
         FILE * fp = fopen(file_path.c_str(), "rb");
         if (fp != NULL)
         {
-            unsigned char *data = malloc(size);
+            unsigned char *data = new unsigned char[size];
             int num_read = fread(data, size, 1, fp);
             fclose(fp);
             if (num_read > 0)