Add task to project

[pr4aveen]

Closes #82

More tests need to be added to test context specific usage.

We might need to redesign how context specific commands work. For example, AddCommand can become abstract. AddTaskCommand and AddProjectCommand can inherit AddCommand. A new issue can be raised for this change if there is time

[codecov-io]

Codecov Report

Merging #83 into master will decrease coverage by 4.89%.
The diff coverage is 56.89%.

@@             Coverage Diff              @@
##             master      #83      +/-   ##
============================================
- Coverage     73.09%   68.20%   -4.90%     
- Complexity      680      695      +15     
============================================
  Files           107      114       +7     
  Lines          2096     2346     +250     
  Branches        233      265      +32     
============================================
+ Hits           1532     1600      +68     
- Misses          482      643     +161     
- Partials         82      103      +21     

Impacted Files	Coverage Δ	Complexity Δ
...ava/seedu/momentum/logic/commands/HomeCommand.java	0.00% <0.00%> (ø)	0.00 <0.00> (?)
...du/momentum/logic/commands/ProjectViewCommand.java	0.00% <0.00%> (ø)	0.00 <0.00> (?)
...omentum/logic/parser/ProjectViewCommandParser.java	0.00% <0.00%> (ø)	0.00 <0.00> (?)
...seedu/momentum/logic/parser/SortCommandParser.java	100.00% <ø> (ø)	14.00 <0.00> (ø)
...c/main/java/seedu/momentum/model/project/Task.java	0.00% <0.00%> (ø)	0.00 <0.00> (?)
...tum/model/project/comparators/DeadlineCompare.java	100.00% <ø> (ø)	3.00 <0.00> (ø)
...java/seedu/momentum/model/util/SampleDataUtil.java	33.33% <0.00%> (ø)	2.00 <0.00> (ø)
...n/java/seedu/momentum/storage/JsonAdaptedTask.java	0.00% <0.00%> (ø)	0.00 <0.00> (?)
src/main/java/seedu/momentum/ui/MainWindow.java	0.00% <0.00%> (ø)	0.00 <0.00> (ø)
src/main/java/seedu/momentum/ui/TimerCard.java	0.00% <0.00%> (ø)	0.00 <0.00> (ø)
... and 48 more

---

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[claracheong4]

I think there are a lot of formatting problems for javadocs aside from the stuff I pointed out.

[khoodehui]

Minor coding style errors, otherwise LGTM

[kkangs0226]

LGTM