Fix for a problem reading wad file

[mindbaffle]

This might help others looking at this. I used a doom1.wad I found and copied it to the web folder and named it doom.wad. After opening the root of this project in the Dart Editor and running it, the code stopped on the WAD_Image.parse line saying that getByteData wasn't defined on a null object. So I had to check to make sure the pname was a valid key by adding "if(header.lumpInfoMap.containsKey(pname))" as you see below in this portion of the wad.dart file. Then it all worked fine.

void readPatches(ByteData data) {
int count = data.getInt32(0, Endianness.LITTLE_ENDIAN);
for (int i=0; i<count; i++) {
String pname = readString(data, 4+i*8, 8);

  if(header.lumpInfoMap.containsKey(pname)) // *added this line*
  { // *added this line*
    WAD_Image patch = new WAD_Image.parse(header.lumpInfoMap[pname].getByteData(data), palette.palettes[0]);
    patchMap[pname] = patch;
    patchList.add(patch);
  } // *added this line*
}

}

[xNotch]

Fixed, thank you