fc-date parsing for timeline span/div tags

[ebullient]

Resolves #97

Given a Timeline span or div with attributes:

<span
    class='ob-timelines'          // ignored (obsidian timelines plugin format)
    data-type='range'             // ignored (obsidian timelines plugin format)
    data-date='144-43-49-00'      // ignored (obsidian timelines plugin format)
    data-end='2000-10-20-00'      // ignored (obsidian timelines plugin format)
    data-fc-date='144-Ches'       // FC: short/mixed (day, hour assumed 0)
    data-fc-end='144-Ches-03-07'  // FC: long/mixed
    data-title='Another Event'
    data-class='orange'
    data-img = 'Timeline Example/Timeline_2.jpg'>
    Event description
</span>

FC Timeline date form has at most 4 segments. THey always starts with the year: yyyy-(mm|mmm)-dd-hh.

[ebullient]

closed to retarget timelines branch