All tEXt chunks are not returned from PngImageParser.getMetadata

According to the PNG spec - Section 4.2.3 - Textual Information -

"Any number of text chunks can appear, and more than one with the same keyword is permissible. "

Unfortunately the PngImageParser.getMetadata method only supports a single tEXt chunk. The problem is in the following line:

final List<PngChunk> chunks = readChunks(byteSource, new ChunkType[]

{ ChunkType.tEXt, ChunkType.zTXt, }

, true);

True is being passed for returnAfterFirst. I believe that false should be passed instead.

I can submit a pull request if you agree.