TextInputFormat does not correctly handle all line endings

The current TextInputFormat readLine method calls break on either a single '\r' or '\n' character. This causes windows formatted text files '\r' '\n' to leave a trailing '\n' character and the next time the readLine method is called on the same input stream it returns a blank string. The patch attached corrects this issue by looking for either single or double character line endings and positions the input stream to the next line. It correctly handles windows, mac, and unix line endings.