Various tidying to Image class
 * Mostly doc fixes
 * Also implement $force for image upload history
Update internal uses of imageinfo() in line with new return format.

Technically a breaking change, but was already broken due to filtering
of data returned by the list handler.

In addition, title is no longer accepted as a param, but rather
canonicaltitle.
Strip out $this->local, not (no longer?) returned by imageinfo
Merge pull request #79 from Jarry1250/image2

Restore image class back to functionality