-Added OpenSSL and HTTPS support

-Built-in version of the library for Windows, Android and iOS (other OSs use system one)
-Small fixes all around

core/io/file_access_pack.cpp

@@ -211,6 +211,7 @@ void FileAccessPack::seek(size_t p_position){
 	}
 
 	f->seek(pf.offset+p_position);
+	pos=p_position;
 }
 void FileAccessPack::seek_end(int64_t p_position){