Implement add task GUI

[jeffsieu]

Tasks can be added using the "New" button and edited by double-clicking or pressing enter on a selected task.

[wlren]

Oi never compile

[codecov-commenter]

Codecov Report

Merging #86 (f370699) into master (b4f5101) will decrease coverage by 3.36%.
The diff coverage is 0.79%.

@@             Coverage Diff              @@
##             master      #86      +/-   ##
============================================
- Coverage     62.03%   58.66%   -3.37%     
  Complexity      535      535              
============================================
  Files           107      108       +1     
  Lines          2057     2175     +118     
  Branches        198      203       +5     
============================================
  Hits           1276     1276              
- Misses          714      832     +118     
  Partials         67       67              

Impacted Files	Coverage Δ
src/main/java/seedu/address/ui/DeletableChip.java	0.00% <0.00%> (ø)
src/main/java/seedu/address/ui/EditTaskDialog.java	0.00% <0.00%> (ø)
src/main/java/seedu/address/ui/MainWindow.java	0.00% <0.00%> (ø)
src/main/java/seedu/address/ui/TaskCard.java	0.00% <0.00%> (ø)
...main/java/seedu/address/ui/TaskFilterChipCell.java	0.00% <0.00%> (ø)
src/main/java/seedu/address/ui/TaskListPanel.java	0.00% <0.00%> (ø)
...c/main/java/seedu/address/ui/TaskListViewCell.java	0.00% <0.00%> (ø)
src/main/java/seedu/address/ui/UiManager.java	0.00% <ø> (ø)
src/main/java/seedu/address/model/task/Task.java	78.57% <100.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update b4f5101...f370699. Read the comment docs.

[yeppog]

Generally looks good but some small styling issues to be fixed

[yeppog]

ok looks good