hit object timing point parsing

[de-odex]

BPM is incorrect (albeit stated in the docs) when ms/beat is negative, and as per https://osu.ppy.sh/help/wiki/osu!File_Formats/Osu(file_format), when ms/beat is negative, it is a percentage of the last inherited timing point

data taken using slider.Beatmap.parse

will attempt fixing

[de-odex]

actually, i'm thinking about why you wouldn't implement this

[llllllllll]

I didn't implement this because I didn't know about this, thanks for letting me know! Also, I hadn't seen that doc, the one that existed when I started slider was much less full, thanks for linking that.