Add icons

Change-Id: Ie55aa8624e138385da1d312926b2538c13dca658
Add more icons

Change-Id: I954abe9f54c0a777bbe76f20bd608954396fdd58
Refactor icons into single static instances

Icons are now constructed in one place and accessed through final static fields.

Change-Id: I1929d04f60d82b1d66d0aef50b1ce1a0eac2486f
Add input validation for tasks

If any required field doesn't have a valid value entered, a error message
shows up, the save button is disabled, and the field is highlighted with a
red border.

Change-Id: I9c378cb4118411dd7f57ce2273bfd96e7a6eb343
Merge branch 'feature/icon' into feature/gui2

Conflicts:
	TaskManager/src/main/java/edu/wpi/cs/wpisuitetng/modules/taskmanager/presenter/TaskPresenter.java
	TaskManager/src/main/java/edu/wpi/cs/wpisuitetng/modules/taskmanager/view/TaskView.java

Change-Id: I23db26435eba7f3e2080e7bc3bc7d6bf7ad13eab
Add more thorough input validation for editing tasks

Tasks can't be updated if no fields have changed, and the option
to "undo" changes is also only avfailable if anything actually
changed.

TaskView now gets its data from a TaskModel instead of re-implementing
all of the getters and setters that are in TaskModel. This makes it
way easier to detect if any changes have been made by the user, and is
more maintainable as we add more fields to TaskModel.

Change-Id: I7f2838deca3b1f947d98609874c5fa37c65d9a89
Activities are now persistant in database, adding autogenerated comments
now

Change-Id: Ic27a1627821841ac9f50a2bae4aa9b2d5479e5db
Use SwingX components for placeholder text in input fields

Such as "Enter a name..." when there isn't a name entered.  This
makes input validation more obvious to the user, and it's much less
buggy than the custom implementation before that we only used for
comments.

Change-Id: Ia2ae8ea92449ccf43859e7831eefd3e7b77808c4
Merge branch 'feature/gui2' into dev