Dr task shade

I changed the color used to highlight worker's tasks on their timeline from blue to yellow. I also fixed the issue that was causing the blue (which is now yellow) to take priority over the task status (i.e. completed, delayed, in progress). For now I disabled the highlighting of a worker's next task with a higher opacity because I spent several hours trying to make it work but kept encountering issues. I will work on that next once this is merged but I wanted to separate them to keep things organized. 

When testing, make sure: 
1) Each worker's tasks on the timeline are properly highlighted in yellow (they should all have the same opacity for the time being)
2) When a worker's task becomes in progress, delayed or completed, it changes from yellow to either blue, red or green, respectively
3) Changes in task status are correctly updated across views