Increase hit target for expand/collapse button

Review Request #3365 — Created Sept. 28, 2012 and submitted — Latest diff uploaded

Information

Review Board

Reviewers

Increase hit target for expand/collapse button

Increase the size of the expand and collapse button images to make it
a bigger hit target. This reduces the chances of someone accidentally 
clicking the user's name while trying to expand/collapse a review.

Fixes Issue #2358
Tested it locally on Chrome Version 22.0.1229 (Mac)