Malformed VTT Cue treated as ok data

[zevlg]

https://w3c.github.io/webvtt/#webvtt-cue-block explicitly specifies that VTT Cue ends with the WebVTT line terminator. However, in the test_parse_captions_with_bom test case the last caption (without WebVTT line terminator) is treated as ok data, but is definitely malformed, because there is no WebVTT line terminator at the end.

[glut23]

Hi @zevlg recent changes in the library were made to be less strict that is essentially closer to what video players are doing with caption files. I fixed the output of the WebVTT files produced to have a line break after the last caption to match the specs. 0.5.1 includes the fix. Thanks for raising the issue.