Fixes some problems with the UIWebView renderer.
Merge pull request #449 from wordpress-mobile/issue/430-black-borders

Fixes some problems with the UIWebView renderer.
Add methods to show and hide failure icon and message when a image upload fails.
Show retry icon before message.
Adjust message font size and position.
Do correct check for element presence in JQ.
Remove id after upload is done.
Merge pull request #450 from wordpress-mobile/issue/348_361_Retry_failed_media_uploads

Issue/348 361 retry failed media uploads