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
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