Fix endOfLineForURLAndContinueScanning parser callback to not treat one character lines as blank

[dcoufal]

Description

This PR fixes issue #1

Change Notes

• The endOfLineForURLAndContinueScanning function was using a <= rather than a < to try to detect blank lines. This meant that one character lines were treated as blank and skipped. Changed to <.
• New unit test testParserWithShortTag to test for this issue.
• This changes uncovered problems in the whole HLSPlaylistTimelineAndSequencingTests suite of tests related to the test playlist strings. They were poorly converted to the new swift ``` format, and did not have correct newline spacing. This was also fixed in this PR.

Pre-submission Checklist

• [x] I ran the unit tests locally before checking in.
• [x] I made sure there were no compiler warnings before checking in.
• [x] I have written useful documentation for all public code.
• [x] I have written unit tests for this new feature.

[CLAassistant]

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