love.graphics.newImage, love.image.newImageData, etc. no longer leave Lua-owned FileData objects floating around waiting to be GC'd when called with filename arguments, resulting in less memory use on startup (resolves issue #890.)

Moved love.filesystem Lua wrapper code from src/modules/filesystem/physfs/ to src/modules/filesystem/.

src/modules/audio/openal/Source.cpp

@@ -658,6 +658,7 @@ int Source::streamAtomic(ALuint buffer, love::sound::Decoder *d)
 {
 	// Get more sound data.
 	int decoded = d->decode();
+	decoded = decoded >= 0 ? decoded : 0;
 
 	int fmt = getFormat(d->getChannels(), d->getBitDepth());