Added new icons to the sprite sheet, shown in the attached image, that

will be used in the Unified Review Banner project. The new icons that

have been added are as follows:

Draft Reply: can be used to show that there are draft replies to review

comments.
File: can be used to show that there are files affected in the review,

for example, the number of files with comments in a review.
Review: can be used to show that there is a review that is currently

in progress.
Create Review: can be used to show that a review can be created.
Edit Review: can be used to show that a review that can be edited.

Manual testing to ensure that the icons show up correctly when the new

CSS classes for each is used (screenshot in the attached image shows the

results of this test).
All JS tests pass.