Draw events to timeline based on start time and row number #48

Fixed issue #48. One _kind of_ breaking change: I added a row field to the event JSON that helps determine where to draw the block. Details are in the code--I'm going to add some comments to the PR so you can see everything that's going on.
Added the row field here. Accesses the global foundry object to determine get the rowHeight and uses snap point to calculate the value.