fix suspension creation by name to return suspension ID
fix Suspension class: do not use DateTime::diff

DateTime::diff is not supported in PHP 5.2 and lower,
but as the actual diff isn't even required here, use
comparison operators instead (PHP >= 5.2.2)
fix mime types for items/rating and suspensions/list (copy-paste errors)
add missing error handling for items/types
bump release version to 0.1.1
Merge branch 'fixes'