EXT-X-START:TIME-OFFSET regEx implemented incorrectly

[will-work]

#1544 implements support for the EXT-X-START:TIME-OFFSET tag, however the regular expression defined in HlsPlaylistParser is incorrect because it does not recognise negative offsets. However, the code in HlsMediaPlaylist that sets the offset is correctly implemented because it does take into account negative numbers.

The fix is therefore a simple one: in com/google/android/exoplayer2/source/hls/playlist/HlsPlaylistParser the string REGEX_TIME_OFFSET should be changed from

private static final Pattern REGEX_TIME_OFFSET = Pattern.compile("TIME-OFFSET=([\\d\\.]+)\\b");
to

private static final Pattern REGEX_TIME_OFFSET = Pattern.compile("TIME-OFFSET=([-\\d\\.]+)\\b");

To reproduce, set the offset value in a media playlist to a negative number and run the demo app.

Reproduced on version 2.2 release using Samsung GT-I9295 (Android 5.0.1 API21)

Logcat snippet:

               com.google.android.exoplayer2.ParserException: Couldn't match TIME-OFFSET=([\d\.]+)\b in #EXT-X-START:TIME-OFFSET=-20
                   at com.google.android.exoplayer2.source.hls.playlist.HlsPlaylistParser.parseStringAttr(HlsPlaylistParser.java:375)
                   at com.google.android.exoplayer2.source.hls.playlist.HlsPlaylistParser.parseDoubleAttr(HlsPlaylistParser.java:383)
                   at com.google.android.exoplayer2.source.hls.playlist.HlsPlaylistParser.parseMediaPlaylist(HlsPlaylistParser.java:287)
                   at com.google.android.exoplayer2.source.hls.playlist.HlsPlaylistParser.parse(HlsPlaylistParser.java:128)
                   at com.google.android.exoplayer2.source.hls.playlist.HlsPlaylistParser.parse(HlsPlaylistParser.java:41)
                   at com.google.android.exoplayer2.upstream.ParsingLoadable.load(ParsingLoadable.java:115)
                   at com.google.android.exoplayer2.upstream.Loader$LoadTask.run(Loader.java:295)
                   at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:422)
                   at java.util.concurrent.FutureTask.run(FutureTask.java:237)
                   at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
                   at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
                   at java.lang.Thread.run(Thread.java:818)

[AquilesCanta]

This is a duplicate of #2495. A fix will be available soon.