Adjust test to handle timing issue on upload modal

ref #1702
-change the tests for the cover and logo image upload modal to
 handle a timing issue in the way they are rendered
Merge pull request #2729 from jaswilli/test-errors

Adjust test to handle timing issue on upload modal
Another adjustment to handle timing issue on tests

ref #1702
-timing issue with the test still exists in #2729 since
 .description is added to the dom after the fact via js
Merge pull request #2730 from jaswilli/test-errors

Another adjustment to handle timing issue on tests
Fix intermittent image upload modal failures

ref #1702
-wait for logo upload modal to go away before beginning test
 for cover upload modal
Merge pull request #2733 from jaswilli/test-error

Fix intermittent image upload modal failures
updateTags refactor

closes #2720
-refactor Models.Posts.updateTags method to reduce complexity
Merge pull request #2726 from jaswilli/issue-2720-tags

updateTags refactor