Fixes issue #235 by adding an onerror function
This could also help by allowing other image hosting site
extensions to leverage the onerror function
Fixes issue #244

The incorrect date stamp was being used. The actual UTC stamp should be
used. This bug was reasonably niche in that it would only appear on the
boundary between two months for a new user created on that day. The
incorrect time zone caused the user to be created in the 'future',
causing a negative difference. Also, the month logic check was incorrect
so even the negative date was wrong, this has been fixed.

I also fixed the leapyear check which was incorrect and had the
potential for bugs at a later date.

I also fixed this for Subreddit Info which had the same issue
showParent selects ".comment .buttons a[href^=#]" for comment parent button. Should be more robust long-term.
showParent - cleanup: just use jQuery             not the superfluous helper function
showParent hides parent comment via reference to  div created in show.  nixed the superfluous helper functions.
showParent bgFix code cleanup for readability
Merge pull request #247 from patricksnape/issue_235

Fixes issue #235 by adding an onerror function
Merge pull request #248 from patricksnape/issue_244

Fixes issue #244
Merge pull request #250 from andytuba/showparent-fix

showParent fixed with better selector