with @qiantong fix lexicon decoder for --surround usage with CTC crit…

…erion

Releasing the code to reproduce the paper 'Sequence-to-Sequence Speec…

…h Recognition with Time-Depth Separable Convolutions'

Releasing the code to reproduce the paper 'Who Needs Words? Lexicon-F…

…ree Speech Recognition'

Releasing the code to reproduce the paper 'Wav2Letter: an End-to-End …

…ConvNet-based Speech Recognition System'

Update decoder.md